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Discussion Starter #1
Well to start the thread off... I've spent countless hours reading forum posts, service manuals, and anything you can name with info on these transmissions. I'm currently having issues with it being stuck in limp mode. I'll give a little info on my rig as I'm new here.

93 Bronco XLT
Built 351w ( when I say built, I mean built... forged internals, custom GT40 heads with every bell and whistle... the works )
MAF conversion with Quarterhorse tuner
Fully built, and updated E4OD ( billet internals, all 4R100 updates the works here as well. )
Over $17,000 invested into the motor and trans alone.

Alright now I'll get to the nitty gritty details. After the motor swap and MAF conversion the truck was running perfectly. The tired old E4OD was even shifting perfectly. One day on the way home from work I went to pull off a stop sign and the truck would barely move, I manually shifted it down and up until I got it home. Dropped the pan and the fluid was smoked, forward clutch packs ate themselves ( or so I thought at the time. ) So I ordered up a custom built E4OD from a very reputable shop. I did not hold back on the build, and had every possible upgrade done to it that is available. ( I'll save the details on that as well as the list is LONG ). So the trans went in back in May, and I fired the truck right up. Trans would shift into 3rd gear when put into OD, and only lower gear I had was 2nd when manually shifting the truck into 2 and 1. Telltale "Limp Mode" issue... So now the fun begins.

I've spent the last few months going through everything on the truck with a fine tooth comb. I'll try to keep the info to a minimum, so here goes.

TPS new and calibrated
ICM updated to the black module in accordance with the MAF conversion
Solenoid connector was replaced with an updated and new one
MLPS updated to new module, and repinned harness ( yes it was aligned correctly )
VSS tests out and is fine
PSOM operates as it should
Updated the recalled SCDS
Checked continuity across the entire trans/abs harness
Pulled apart, cleaned, and greased every electrical connector in the engine bay, and trans.
Tried a new PCM just incase my rebuilt unit was faulty ( no luck )
Manually tested the Solenoid Pack and it tested out.

I'm sure I'm missing something as I've poured countless nights/weekends into the truck trying to figure out wtf is going on with it.... But as far as I can tell I've left no stone un turned, so I'm stumped. My trans builder has no idea either, and I've scoured the service manuals testing everything that they say can cause the Limp Mode issue. And the weirdest thing about the whole ordeal is I'm not getting a single code, NO CODES, NO OD LIGHT FLASHING.

Anyone have any idea what the hell is happening here? I'm to the point of ripping the entire interior out of the truck, pulling all the wiring harnesses and re-wiring the truck from the ground up. That or buying a PCM for a manual MAF truck, and a Baumann stand alone controller for the trans.

Thanks for any and all help! It's much appreciated.
 

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was there ever any analysis as to why the original trans failed? it sounds like we possibly addressed a symptom with the new trans but not the actual problem which killed the first one.

i'm not familiar with the Quarterhorse offering - do you know if the PCM was made to work with the E4OD?
 

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Discussion Starter #3
First trans was old and tired, and the 30 mile drive home in limp mode ended up taking out the forward clutch pack, mostly because I didn't get a warning light and wasnt aware it was in limp mode right away.

The PCM is a 94 MAF truck PCM with E4OD. It worked perfectly with my old trans for a few thousand miles before the limp mode BS showed up. It uses the same strategy as a HOG0 PCM for tuning, which is the AHACB strategy.
 

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Yo Flowcus,
WELCOME!
Limp Mode aka "Failure mode effects management (FMEM) is an alternate system strategy in the powertrain control module (PCM) designed to maintain vehicle operation if one or more sensor inputs fail. When a sensor input is perceived to be out-of-limits by the PCM, an alternative strategy is initiated. The PCM substitutes a fixed value and continues to monitor the incorrect sensor input.
In this mode, engine power and vehicle speed are reduced, while full function of the power steering, power braking, lighting, and climate control systems are maintained.
If the suspect sensor operates within limits, the PCM returns to the normal engine running strategy.
Engine Running DTC 98 or 998 will be displayed when FMEM is in effect.
The Malfunction Indicator Lamp (MIL)/Message (AKA CEL) will remain on when FMEM is in effect." by Ford

E4OD Transmission Control Indicator Light (TCIL) is a LED and overdrive on/off switch at end of the Transmission shifter stalk; flashing OD light is an indication of a transmission related trouble code in the Powertrain Control Module (PCM).
Is it flashing while driving?


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.


BBL
 

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I know you said "no codes" but did you look for the CM (Memory) codes? The code 452 is a CM code, it DOES NOT light the Check Engine light. The 452 indicates that the PCM has lost the VSS signal. With no VSS signal, the PCM put the E4OD line pressure at maximum and the trans shifts as if you were at WOT. Here's the signal flow from the VSS pick-up in the rear axle to the PCM. Notice that there are a couple of splices and a couple of connectors between the PSOM and the PCM. (You said the PSOM was working correctly, but that doesn't mean the signal isn't being lost between the PSOM and the PCM.)


https://www.supermotors.net/registry/media/1073513

(I had an intermittent loss of the VSS signal, by intermittent, my '94 would lose the signal once or twice a YEAR! I eventually got fed up trying to find it, and threw a PSOM at it and installed the jumper denoted on the schematic. My problem has not recurred in 5 years.)
 

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Discussion Starter #6
I know you said "no codes" but did you look for the CM (Memory) codes? The code 452 is a CM code, it DOES NOT light the Check Engine light. The 452 indicates that the PCM has lost the VSS signal. With no VSS signal, the PCM put the E4OD line pressure at maximum and the trans shifts as if you were at WOT. Here's the signal flow from the VSS pick-up in the rear axle to the PCM. Notice that there are a couple of splices and a couple of connectors between the PSOM and the PCM. (You said the PSOM was working correctly, but that doesn't mean the signal isn't being lost between the PSOM and the PCM.)


https://www.supermotors.net/registry/media/1073513

(I had an intermittent loss of the VSS signal, by intermittent, my '94 would lose the signal once or twice a YEAR! I eventually got fed up trying to find it, and threw a PSOM at it and installed the jumper denoted on the schematic. My problem has not recurred in 5 years.)
I'm using an Innova obd1 code reader to pull codes. It checks the CM codes as well. KOEO I get TAB and TAD codes 553 and 552 which do not show on KOER as they're tuned out with the quarterhorse as all the SMOG equipment has been removed. Otherwise no other codes are present, and KOER nothing as well.

I already pulled the trans harness and checked continuity across that, and checked for signal at the VSS, but did not check return signal at the PCM for the VSS so I'll have to do that tonight. I just wish the damn thing would throw a code. I havent taken the truck out on a long drive as I'm only able to utilize 2nd and 3rd gears, and I really do not want to cause any damage to my very expensive E4OD.
 

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Discussion Starter #7
Yo Flowcus,
WELCOME!
Limp Mode aka "Failure mode effects management (FMEM) is an alternate system strategy in the powertrain control module (PCM) designed to maintain vehicle operation if one or more sensor inputs fail. When a sensor input is perceived to be out-of-limits by the PCM, an alternative strategy is initiated. The PCM substitutes a fixed value and continues to monitor the incorrect sensor input.
In this mode, engine power and vehicle speed are reduced, while full function of the power steering, power braking, lighting, and climate control systems are maintained.
If the suspect sensor operates within limits, the PCM returns to the normal engine running strategy.
Engine Running DTC 98 or 998 will be displayed when FMEM is in effect.
The Malfunction Indicator Lamp (MIL)/Message (AKA CEL) will remain on when FMEM is in effect." by Ford

E4OD Transmission Control Indicator Light (TCIL) is a LED and overdrive on/off switch at end of the Transmission shifter stalk; flashing OD light is an indication of a transmission related trouble code in the Powertrain Control Module (PCM).
Is it flashing while driving?


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.


BBL
The MLPS has been changed to the updated one, and aligned properly. The truck does not shift at all, in OD it's in 3rd gear, and when shifted into 2nd or 1st manually it stays in 2nd gear. The only hard engagement is reverse, otherwise that's where the truck is at. I'm afraid to drive it any distance as I do not want to damage this expensive transmission. I have driven it lightly down my country back roads for about 10 miles or so by shifting manually into 2nd and then up shifting into OD which defaults to 3rd. Still no code, or flashing OD light.
 

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i don't know what your tuner can read but...

when i was running into a similar issue that i couldn't solve, i ended up taking it to a transmission shop that i knew was knowledgeable on old fords. they put it up on the lift and ran it through the gears. at the same time, they hooked up a diagnostic reader and could see that periodically / sporadically / every now and then the speed signal would drop to 0 for a split second and then pick back up again.

ultimately, i bypassed everything as outlined by @Mikey350 and well...i haven't had to do anything since.

i don't know if they were simply reading the speedometer feed or what, but it was all fast enough that it didn't register on the speedometer on the dash. so you might try reading the speedometer (or any other speed signal you can find in your tuner) and see what it shows.
 

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Discussion Starter #10
@Mikey350 No chance its misaligned, I've double triple checked that over the last couple months. I've got a sneaking suspicion there is a bad wire somewhere causing a miss communication with the PCM. In the 2 years I've owned the rig I have found several Jerry rigged harness splices where the PO used crimp connectors, with no heat shrink tube or tape. I'm in the process of removing the interior to clean up the wiring harnesses in there now, and solder them together properly.

Since its labor day weekend I'm heading out of town to my cabin for some fishing and relaxation. If anyone has any other suggestions on what to look at next, I'll gladly give it a go when I'm back in the vicinity of the truck. That VSS signal return will be the first thing I check.
 

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Discussion Starter #11
@dash_cam With the Quarterhorse, and Zietronix wide band I can data log every single variable the PCM monitors and then some. But I do not believe it can run an electrical diagnostic to monitor signal loss at the PCM. Pretty sure I'd need a Breakout Box to do that... I'm gonna have to go back over the VSS harness, and check for signal return at the PCM on that like Mikey suggested.
 

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@Mikey350 No chance its misaligned, I've double triple checked that over the last couple months. I've got a sneaking suspicion there is a bad wire somewhere causing a miss communication with the PCM. In the 2 years I've owned the rig I have found several Jerry rigged harness splices where the PO used crimp connectors, with no heat shrink tube or tape. I'm in the process of removing the interior to clean up the wiring harnesses in there now, and solder them together properly.

Since its labor day weekend I'm heading out of town to my cabin for some fishing and relaxation. If anyone has any other suggestions on what to look at next, I'll gladly give it a go when I'm back in the vicinity of the truck. That VSS signal return will be the first thing I check.
Make sure that the G100 and G200 grounds are good, maybe even take them apart and clean up the mounting bolts and connectors with a little emery cloth. A flaky ground could cause that VSS signal to drop out. Good luck fishing!
 

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Discussion Starter #13
Well I ran the signal jumper from the PSOM to the PCM, and no luck. Checked and cleaned all grounds, still no luck... Very stumped with the situation here, anyone have any other info or shit I could try?
 

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Well I ran the signal jumper from the PSOM to the PCM, and no luck. Checked and cleaned all grounds, still no luck... Very stumped with the situation here, anyone have any other info or shit I could try?
Did you ever figure out the problem brother same stuff happening to me
 
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