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Discussion Starter #1
So I've had my bronco for little over a year now, and I've done nothing major but just simply replace parts as they break. But for a few months now I've had this problem which is just aggravating! I can get in the truck, drive around town and it'll act just fine as long as I'm soft on the rpms, But it seems that once i go above 2000 rpms it'll throw the truck into "limp mode" and the tranny will buck really hard, especially in reverse! I've replaced the tps, iac, icm, the computer and so forth, idk if I'm missing anything if y'all know what the problem could be but I'm stumped, tried pulling codes but nothing is popping up!
 

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Discussion Starter #3
its like it trips a sensor or something cause it only does it when i get it over 2000 rpms, but once it does it, ill drive it home or pull over, take the battery cables off for a few mins, hook them back up and it won't buck until i give it a lot of gas to make it shift high or put it on the highway and get above 2000 rpms or about 65mph
 

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Discussion Starter #5
checked for codes, only thing i got was low voltage in the tps, fixed it and no changes, cleared the code and still nothing, its a 1995 with the 5.8L. no flashing of the od light, I'm just puzzled
 

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I have a buddy at work that has a Bronco II doing about the same thing. However, he suspects the TC is locked because when he shifts into reverse once its in "Limp mode" the engine will die.
 

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Discussion Starter #7
well mine doesn't do that, but when its in limp mode, ill put it in reverse and it'll shift like a race car lol. talked to some tech guys at the ford dealership and they suspect it might be a "high speed misfire"? not sure what to check for if its that.
 

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Discussion Starter #8
just a little update, I'm gonna try replacing a few parts this weekend from what i read on here, coil, instrument cluster, speedo sensor and maybe a fuel pump, after that I'm out of idea's
 

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throw some more money at it. Because putting on new parts has to be the answer.

If it is bucking and the trans is going into limp mode then it is getting a error and you should be able to read them.
 

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that's a lot of money and time to throw at it. has your filter n fluid ever been changed?

you might have to take it to a tranny shop that can check for tranny specific codes that ECM wont read. after doing a shiftkit in my tranny it constantly had OD flashing and would shift HARD. scanning for codes showed all good. took to tranny shop and they scanned the tranny for problems and revealed a bad pressure regulator valve.

does your speedometer work correctly?
 

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yo cam;
btw, I'll begin with describing the commonly used erm "limp mode" first, then get to Ford's description.

If all the shifts are hard, PCM is going into limp mode that causes E4OD to shift hard because the pressures are increased.
PCM goes into limp mode when it senses an error in the transmission shifting or electrical system.
The most common cause for this is the Manual Lever Position (MLPS) also called Transmission Range (TR) Sensor. This is the sensor that is bolted to the drivers side of the transmission case with the shift lever arm going through the center of the sensor.
Try disconnecting the battery for 15 minutes with the headlamps on. This should clear the limp mode and return the transmission to normal shift strategy. If it does then the problem is intermittent.
If it still shifts hard then the fault is continuously occurring. It is possible that there is another input/output signal problem, but 99% of the time it is the MLPS/TR sensor especially if it clears limp mode proving the problem is intermittent.

happens when the vehicle computer recognizes a problem in it's logic. When an expected signal value from a sensor is sent to the computer and is not within the computer's programmed specifications, "secondary" programs are activated by the computer to strive to protect the transmission from damage the improper sensor signal might cause to occur.

In other words, the computer is always expecting certain signal values from certain sensors i.e. the temperature sensor, the speed sensor, the throttle position sensor, etc. As long as these signals are what it would normally expect for the conditions and is normal based on all the other signals it is receiving from other sensors, it acts normally and accordingly.

If the computer, all of a sudden, receives some crazy signal from one of the sensors that is out of the normal range expected from this sensor, it will go to "emergency" or "secondary" measures.

These emergency measures vary depending on the severity of the defective signal. All this is preprogrammed into the computer's logic by the manufacturer. The manufacturer has decided that as long as a certain parameter of a particular signal is sent from a sensor to the computer, all is well. The manufacturer decided that if this signal is higher than their highest parameter or lower than their lowest parameter, something is wrong with that sensor and the computer should make someone aware of the situation and take action to try to "save" the vehicle systems or powertrain.

Perhaps the computer will simply cause the "check engine" light to come on. The signal variation wasn't severe or critical to cause any mechanical failures but the vehicle's operator is made aware that he or she should have the vehicle checked out electronically to see if a minor sensor has broken down or is starting to send the odd erratic signal. This type of condition is commonly referred to as a "soft code". Normal functions are not affected but if the repair is not made, performance or fuel efficiencies might suffer. Perhaps the sensor only malfunctioned one time and all other times was fine. This might be an early warning of a sensor that is beginning to fail or has a loose connector or connection.

Other times the signal needed to perform operations normally is so far out of specification that the computer has no choice but to go into survival mode. With transmissions, the computer will cause the internal tranny fluid line pressure to default to high to protect clutches and bands. The transmission also turns off the shift solenoids to cause the unit to default to a single gear, usually second or third. All normal instructions to control line pressure are overridden so a hazardous "slipping condition" cannot occur easily. This theoretically is so that the vehicle's driver can get the damaged vehicle to the next town for repairs. This condition is commonly called "Limp Mode" for this reason. You limp to the next town in second or third gear only, at full line pressure so the tranny guts won't slip on your trip in.

By the way, interestingly and just as a side note, if the cable harness going to your transmission was ever to become detached, severed or damaged, your transmission would also go to "limp mode".
...
miesk5 note; check it on passenger side of trans.

E4OD solenoid body connector seating by SeattleFSB
...
The vehicle's computer would immediately sense that it has lost contact with the transmission and would set the codes and send "limp mode" signals to the tranny. But because the harness is severed between the computer and the transmission, no computer signals will reach the transmission. These sent signals, however, would have had the identical affect on the transmission as what taking away supplied power to the shift and line pressure solenoids has as in the case of a transmission harness being detached or cut. Due to the engineered voltage strategies of the solenoids, the transmission simply defaults to a single gear and line pressure defaults to high, all in order to "limp" you home.

A Throttle Position Sensor that improperly sends a reading that it is wide open when in fact it is physically closed would be detected by the computer when it compared this reading with the vehicle speed sensor that perhaps is showing very slow vehicle speed. The signal, by itself can't be considered wrong but when put against all the other sensor signals of the system might cause a computer concern. The computer, at this point, unable to "trust" the collection of signals because together they are not making sense in it's logic, will simply go to limp mode in the transmission to protect it and make the operator aware that something is wrong with one of the sensors and a mechanic's attention is needed to correct the situation.

Source: by Greg O at autotransinc.com via webarchive.org

==========

TSB: 88-05-07
http://www.revbase.com/BBBMotor/TSb/DownloadPdf?id=23128
Excerpts;
"...CHECK ENGINE light will come on while engine is operating in Failure Mode Effects Management (FMEM) or Hardware Limited Operation Strategy (HLOS) modes. The light will stay on as long as the fault causing it is present. In FMEM mode, the computer is receiving a sensor signal that is outside the limits set by the calibration strategy. In this mode, the computer uses an alternate strategy to maintain reasonable vehicle operation in spite of the fault. The following chart lists the system faults which will turn on the CHECK ENGINE light in this mode. The error code associated with this system fault is stored in Keep Alive Memory (KAM). If the fault is no longer present, the light will turn off and vehicle will return to normal vehicle strategy. The error code stored when the light was on was not erased. This code is one of the continuous error codes and can be accessed by running the KOEO self-test.

HLOS mode is used when the system fault(s) is too extreme for the FMEM mode to handle. In HLOS mode, all software operations have stopped and the computer is running on hardware control only. The default strategy for this mode has a minimal calibration just to allow the vehicle to operate until it can be serviced.
IN HLOS MODE YOU WILL NOT GET ERROR CODES..."
 

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just a little update, I'm gonna try replacing a few parts this weekend from what i read on here, coil, instrument cluster, speedo sensor and maybe a fuel pump, after that I'm out of idea's
There's no need to do all of that just yet. Pull the codes and then go at it. Wouldn't hurt to pull and inspect/clean the speedo sensor at least.
 

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yo,
This is by Ford for a 96, but similar exc for any OBD II info;

96 Bronco-F-Series Workshop Manual (PARTIAL) by dieseldave
http://www.diesel-dave.com/vehic/manual/stj/stjleft.htm


Section 07-01A: Transmission, Automatic, E4OD
http://www.diesel-dave.com/vehic/manual/stj/stj71a24.htm#extract_1037
Diagnosis by Symptom

I chose this Symptom; look @ others as well that are closer to your issue(s)

Shift Concerns: Timing — Erratic/Hunting (Some/All)


Possible Component
Reference/Action

212 — ELECTRICAL ROUTINE
Powertrain Control System •Perform Shift Point Road Test and Torque Converter Operation Tests.

•Vehicle wiring harnesses, powertrain control module, electrical inputs/outputs, throttle position sensor, transmission fluid temperature sensor, shift solenoid 1, shift solenoid 2, transmission range sensor, torque converter solenoid
•Run On-Board Diagnostics.
*miesk5 Note, this is the Code Test & did you and shop do both KOEO AND KOER tests?*
Service as required. Clear codes, road test and rerun On-Board Diagnostics.

With Speed Control "ON"
•Torque converter cycling

•Shift cycling (3-4 / 4-3 shifts)
•Re-evaluate with Speed Control OFF or depress transmission control switch (overdrive cancelled). If condition still exists, proceed with diagnosis.

312 — HYDRAULIC/MECHANICAL ROUTINE
Fluid
•Improper level
•Adjust fluid to proper level.

Filter Assembly and Seal
•Plugged, damaged
•Inspect filter assembly and seal for damage. Service as required.

•Filter seal damaged

Main Control
•Valves, accumulators, damaged, stuck
•Inspect for damage. Service as required.

•Bolts not tightened to specification
•Retighten bolts to specification.

•Gaskets damaged
•Inspect for damage and replace.

•Wrong parts used in rebuild
•Verify that proper parts were used.

Torque Converter Clutch •Refer to Torque Converter Cycling (No. 342).

For further diagnosis for timing issues, refer to Reference/Action •Refer to the following shift routine(s) for further diagnosis:
 

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just a little update i did get a code 212 when i ran the tests over and over.
A code 212 on a '95 (OBD-1) can be caused by having the wrong ICM, you should have a black one, regardless of what the auto places might try and sell you.

And please put the year of your Bronco in your signature so we don't have to screw around trying to find it. You'll get more replies.
 

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yo, As MIKEY Advised;
DTC 212; "...IDM is a feedback signal generated by the ignition system and is monitored at pin #4 of the ECM. Its purpose is to diagnose missed ignition primary pulses at the time the ECM commands the Spout signal to fire the coil. Since it is used solely for diagnostic purposes, if this circuit is not operating properly, it will not affect vehicle driveability; & by Seattle FSB- The Ignition Diagnostic Monitor (IDM) signal is a diagnostic signal for the PCM to to verify a coil firing for each PIP signal. If an erratic or missing IDM signal is received, a Diagnostic Trouble Code (DTC 212) is set. An occasional IDM signal may not affect drivability, but can still throw a trouble code. As SigEpBlue has stated, check for an intermittent ground on the spOUT and/or IDM circuit. Also, ensure that you have the correct Ignition Control Module (ICM) and it is wired correctly to the PCM..." miesk5 NOTE; use BLACK modules in 1994-1996 Broncos
Source: by SMP via SigEpBlue (Steve) & by Seattle FSB (SeattleFSB) at http://www.fullsizebronco.com/forum/...d.php?t=127508


and;
DTC 212 (Ignition module circuit failure-SPOUT circuit grounded); Check spout connector is secure or replacing it w/bare copper wire. If that doesn't help any try checking the wiring


DTC 212; "...IDM is a feedback signal generated by the ignition system and is monitored at pin #4 of the ECM. Its purpose is to diagnose missed ignition primary pulses at the time the ECM commands the Spout signal to fire the coil. Since it is used solely for diagnostic purposes, if this circuit is not operating properly, it will not affect vehicle driveability; & by Seattle FSB- The Ignition Diagnostic Monitor (IDM) signal is a diagnostic signal for the PCM to to verify a coil firing for each PIP signal. If an erratic or missing IDM signal is received, a Diagnostic Trouble Code (DTC 212) is set. An occasional IDM signal may not affect drivability, but can still throw a trouble code. As SigEpBlue has stated, check for an intermittent ground on the spOUT and/or IDM circuit. Also, ensure that you have the correct Ignition Control Module (ICM) and it is wired correctly to the PCM..." Miesk5 NOTE; use BLACK CCD Ignition Modules in 94-96 Broncos
Source: by SMP via SigEpBlue (Steve) & by Seattle FSB (SeattleFSB) at http://www.fullsizebronco.com/forum/showthread.php?t=127508
==============

BTW, as I mentioned in another thread here; In place of the breakout box, go to the EEC pin instead


EEC Connector Pin Diagram
Source: by Fireguy50 (Ryan M)


EEC Connector Pin LEGEND Bronco & Ford Truck & Van: 4.9, 460, 5.0, 5.8; miesk5 Note, see his Connector Pin Diagram Link above)
Source: by Ryan M (Fireguy50) at http://web.archive.org/web/20131029020805/http://oldfuelinjection.com/truckpinouts.html
THIS IS BY fORD

DTC 212 indicates a loss of IDM input to the PCM; "...
Open harness circuit.
Shorted harness circuit.
Damaged Ignition Control Module (ICM).
Damaged Powertrain Control Module (PCM).
Key off.
Disconnect Powertrain Control Module (PCM). Inspect for damaged or pushed out pins, corrosion, loose wires, etc. Service as necessary.
Install breakout box, leave PCM disconnected.
Disconnect Ignition Control Module (ICM).
Measure resistance between Test Pin 4 at the breakout box and IDM circuit at the ICM vehicle harness connector.
Is resistance less than 5.0 ohms?
Yes GO to NA5 .
no SERVICE open circuit. REMOVE breakout box. RECONNECT PCM. CLEAR Continuous Memory. RECONNECT all components. RERUN Quick Test.

NA5 CHECK IDM CIRCUIT FOR SHORTS TO POWER (EXCLUDING VREF)
Key off.
Breakout box installed.
PCM and ICM disconnected.
Measure voltage between Test Pin 4 at the breakout box and battery negative post.
Key on, engine off.
Measure voltage between Test Pin 4 and Test Pins 40 and 60 at the breakout box.
Is any voltage reading greater than 10.5 volts?
Yes SERVICE short circuit. REMOVE breakout box. RECONNECT all components. RERUN Quick Test.
No GO to NA6 .

NA6 CHECK IDM CIRCUIT FOR SHORTS TO VREF AND PIP
Key off.
Breakout box installed, PCM disconnected.
ICM disconnected.
Ignition coil disconnected on Non-CCD vehicles (refer to Pinpoint Test Schematic ).
Disconnect Scan Tool from Data Link Connector (if applicable).
Note: For proper results of this test, the Scan Tool must be disconnected. Due to the circuitry of the Scan Tool and the vehicle, voltage can be fed to the VREF circuit giving a false indication of a short to power.
For Shorts To VREF: Measure resistance between Test Pin 4 and Test Pin 26 at the breakout box.
For Shorts To PIP circuit: Measure resistance between Test Pin 4 and Test Pin 56 at the breakout box.
Is each resistance greater than 10,000 ohms?

Yes gO to NA7 .
No SERVICE short circuits. REMOVE breakout box. RECONNECT all components and SCAN Tool (if applicable). RERUN Quick Test.

NA7 CHECK IDM CIRCUIT FOR SHORT TO GROUND
Note: During this check when 4-wire HO2S is connected to the vehicle harness on DI vehicles, a short to SIG RTN (Pin 46) may be indicated in conjunction with an actual PWR GND short.
Key off.
Breakout box installed, PCM disconnected.
ICM disconnected.
Scan tool disconnected from Data Link connector.
Ignition coil disconnected on Non-CCD vehicles (refer to Pinpoint Test Schematic ).
Measure resistance between Test Pin 4 and Test Pins 20, 40, 46 and 60 at the breakout box.
Is each resistance above 10,000 ohms?
Yes RECONNECT Scan Tool. GO to NA8 .

No REMOVE breakout box. SERVICE short to ground in IDM circuit. RECONNECT all components. CLEAR Continuous Memory. RERUN Quick Test.


NA8 CHECK ICM
Key off.
Breakout box installed.
Connect PCM to breakout box.
Reconnect ignition coil and ICM.
Connect DVOM between Test Pin 4 and Test Pin 16 at the breakout box.
Start engine.
Observe DVOM when voltage is allowed to stabilize.
Lightly tap on ICM to simulate road shock.
Wiggle ICM connector (for 3.8L AX4S, 3.8L RWD, 3.0L, 7.0L and 7.5L Trucks, wiggle ICM, GCM and CMP sensor connectors).
A sudden change in voltage indicates a fault.
Is a fault indicated?
Yes DISCONNECT and INSPECT connectors. If connector and terminals are good, REMOVE breakout box, RECONNECT all components and REFER to Section 8A , DI Diagnostics (2.0L Probe, Section 8B).
No GO to NA9 .

NA9 CHECK EEC HARNESS
DVOM still connected between Test Pin 4 and Test Pin 16 at the breakout box.
Key on, engine running.
While observing a voltage change as in NA8 , perform the following: Grasp vehicle harness closest to ICM connector (for 3.8L AX4S, 3.8L RWD, 3.0L, 7.0L and 7.5L trucks, wiggle ICM, GCM and CMP sensor connectors). Shake and bend a small section of the EEC harness while working toward the dash panel. Also wiggle, shake and bend the EEC harness from dash panel to PCM.
Is a fault indicated?
Yes ISOLATE fault and SERVICE as necessary. REMOVE breakout box. RECONNECT all components. CLEAR Continuous Memory. RERUN Quick Test.
No GO to NA10 .

NA10 CHECK PCM AND HARNESS CONNECTORS
Key off.
Disconnect Powertrain Control Module (PCM). Inspect for damaged or pushed out pins, corrosion, loose wires, etc.
Are connectors and terminals OK?
Yes GO to NA11
No SERVICE as necessary. REMOVE breakout box. RECONNECT all components. CLEAR Continuous Memory. (REFER to Quick Test Appendix, Section 5A .) RERUN Quick Test.

NA11 CHECK PCM FOR SHORT TO POWER
Key off.
Breakout box installed.
PCM connected to breakout box. For vehicles with Remote Mounted ICM and Camshaft Position (CMP) sensor: Disconnect ICM and CMP.
7.0L Truck: Also disconnect Governor Control Module (GCM).
All others: Disconnect ICM.
Measure voltage between Test Pin 4 and chassis ground.
Key on, engine off.
Measure voltage between Test Pin 4 and Test Pins 40 and 60 at the breakout box.
Is any voltage reading greater than 10.5 volts?

Yes REPLACE PCM. REMOVE breakout box. RECONNECT all components. RERUN Quick Test.
No GO to NA12 .

NA12 CHECK PCM FOR SHORT TO GROUND
Key off.
Breakout box installed.
PCM connected to breakout box.
Ignition coil (Non-CCD only), ICM and CMP sensor disconnected.
Measure resistance between Test Pin 4 and Test Pins 40, 46 and 60 at breakout box.

Is each resistance greater than 10,000 ohms?
Yes rEMOVE breakout box. RECONNECT all components. For further diagnosis, REFER to Section 8A , DI Diagnostics (Probe, Section 8B).

No REPLACE PCM. REMOVE breakout box. RECONNECT all components. RERUN Quick Test.
==========


95 Bronco 5.8 Ignition Wiring Diagram
http://www.revbase.com/BBBMotor/Wd/DownloadPdf?id=46706
 

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Perfect description of a problem I had with an 82 bronco years ago. Was a bad ignition coil. Mine was obvious due to it leaking oil. unplug yours for a quick visual inspection and it might just be that simple.
 

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Ditto on this one.

Ages ago now on my Green 94, I had much of the same issues. The transmission shop I was talking to, listened to the symptoms and recommended I take it in to my local shop for a tune. His magic words, "high speed miss", and yes, it was pretty dramatic at freeway speeds.

The spark plugs were worn, the rotor was worn.. essentially the ignition system downstream of the coil was adding a heap more resistance than designed. The coil was compensating with more voltage which added to the wear, the coil added more, more wear.. until the system was all but done.

One fairly heavy tune, problem gone.

Check plugs, rotor, the cap, plug and coil wires. May or may not need all of those or the coil, but essentially a good tune may get it. On mine, the coil did get changed too, but it was not the cause of the problem.

Driveability issues .. by the symptoms you'd swear the transmission was coming apart, you were being shot at or were running over a lot of wheelchairs.. it was just nasty and wrong!

Nick

Perfect description of a problem I had with an 82 bronco years ago. Was a bad ignition coil. Mine was obvious due to it leaking oil. unplug yours for a quick visual inspection and it might just be that simple.
 

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Discussion Starter #20
So I finally took the truck to a tranny shop and got all the codes tested, came back with the dreaded code (628) or slippage of the torque converter, and from hearing everyone's opinions on this my symptoms match up to this, lack of throttle, shift points are off, erratic idle, truck feels very boggy and under high loads will go into limp mode with the code 628 showing
 
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