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Engine Codes

4K views 15 replies 6 participants last post by  miesk5 
#1 ·
First I would like to thank everyone for their knowledge, and willingness to help others with their issues! I have learned alot from some of the threads. That being said, I am new to the Bronco scene. I just bought a 94 XLT to fix up, and it has several issues to fix. I already know that the fuel pump needs replaced. It was idling down till it stalled out completely, so I replaced the IAC valve. Now it idles, but RPMs go up and down. I then had my CEL come on. So I grounded my STI to get the codes, here's what I got- 21, 22, 23, 67, 87, 94. I was hoping someone could shed a little light on them, along with possible causes and solutions. Thank you.
 
#2 ·
Man, I wish I could tell you that it is simply a secret switch or sensor that that could cure all of your problems, but it is time to develop a relationship and get intimate with your new Bronco.



Although I would immediately focus on the TPS and clearing the Keep Alive Memory, start with this:


• Lack of fuel system control (excessively rich or lean)
Test Fuel Pressure/replace old Fuel Filter

• Throttle sticking or binding.
Remove and clean Throttle Body/Test TPS sensor

• Contamination within the idle speed control device
Disconnect the battery Negative for 5+ minutes to delete the KAM

• Engine not reaching operating temperature
Allow engine to warm up to Normal Operating Temperature/Replace Thermostat

• Incorrect ignition timing CHECK
Time engine to 10 degrees BTDC/ Check Spark Plug Gap and condition

• Incorrect or clogged PCV system
Test/replace Positive Crankcase Ventilation System Valve and check Breather Tube & Filter from the Air Box

• Vacuum leaks (intake manifold, vacuum hoses, vacuum reservoirs, power brake booster, etc. Manifold Absolute Pressure (MAP) systems will increase idle with vacuum leak and Mass Air Flow (MAF) will decrease idle with vacuum leak)
Use a vacuum tester to test/replace any and all suspect vacuum lines and Reservoirs


Clear codes and try again. Then we can focus on the EGR and Thermactor Emissions System.
 
#3 · (Edited)
yo

DTC 94 (R) Air passages for Thermactor Air System on the left side is clogged or HEGO is going bad; or Transmission TCC circuit/solenoid problem
Source: by miesk5 at FSB

DTC 87, 95 & 96; "...These codes relate to low or no power reaching the fuel pump. Start testing at the fuel pump relay. The relay must respond to the EEC processor and the relay contacts must be a low resistance path for fuel pump power. Relay testing can be done in a couple minutes with the fuel pump test table. Fuel pump relay testing;1. Use solenoid test at EEC pin 22 to check relay coil current draw. 2. Voltage at pump power terminal must be within .5v of battery power when relay is turned on with amp meter at pin 22. Check power from battery if voltage is low. Check the inertia switch and fuse if battery voltage is missing. Pin 22- (light blue-orange) Grounded to turn "on". Voltage will drop to about 1v when "on". Current draw will be 160 to 270mA Pin 8- fuel pump monitor (dark green-yellow) 0v engine off, battery voltage with engine running..."
Source: by Dustin S (Dustball, Mellow Yellow, Mr. Laser Boy) at FSB https://www.fullsizebronco.com/forum/showthread.php?t=155384


DTC 67 and 634 indicate the MLP sensor is out of Self-Test range when the gear selector is in PARK. DTC 522 and 654 indicate the gear selector was not in Park during Self-Test.
DTC 67 & DTC 634; Manual Lever Position/Transmission Range (MLP/TR) Sensor Pin-Point Test in 92-96; from Ford EVTM; "...Check the resistance of the MLPS: The resistance of the MLPS (pins 30 and 46).." read more


DTC 23, 53, 63, 121, 122, 123; "...Symptoms of a BAD TPS: The one thing that you can definitely count on, when the TPS fails, is the Check Engine Light shining nice and bright to let you know that there's a Diagnostic Trouble Code stored in the Fuel Injection Computer. Here are some specific symptoms you'll see: 1.TPS Diagnostic Trouble Codes (DTC’s) stored in the vehicle’s computer’s memory. Seattle has an A#1 Testing, Replacement and Adjustment article here @ https://www.fullsizebronco.com/forum/showthread.php?t=203080


DTC 22 or 126 indicates the Manifold Absolute Pressure (MAP) sensor is out of Self-Test range. Correct MAP range of measurement is typically from 1.4 to 1.6 volts. Do NOT use an ordinary voltmeter to check a Ford MAP sensor because doing so can damage the electronics inside the sensor. This type of sensor can only be diagnosed with a DVOM that displays frequency, or a scope or scan tool. Also make sure engine manifold vacuum is within specifications at idle. If vacuum is unusually low due to a vacuum leak, retarded ignition timing, an exhaust restriction (clogged converter), or an EGR leak (EGR valve not closing at idle). A low intake vacuum reading or excessive backpressure in the exhaust system can trick the MAP sensor into indicating there is a load on the engine. This may result in a rich fuel condition. A restriction in the air intake (such as a plugged air filter), on the other hand, may produce higher than normal vacuum readings. This would result in a load low indication from the MAP sensor and possibly a lean fuel condition. Possible causes: circuit open between sensor vehicle harness connector and PCM. circuit shorted to VREF, SIG RTN, or GND. Damaged MAP sensor. Vacuum trapped at MAP/BARO sensor. Unusually high/low barometric pressure. Kinked or obstructed vacuum lines (MAP). Basic engine (valves, vacuum leaks, timing, EGR valve, etc.). High atmospheric pressure. Damaged PCM. VREF circuit open at MAP sensor. SIG RTN circuit open at MAP sensor. The pinpoint test directs you to check the voltage to the MAP sensor. With the MAP sensor connected, use paper clips to back probe the MAP connector so you make contact with the terminals inside the connector by inserting the paper clips into the bak of the connector. This allows you to get voltage readings while the connector is plugged in. The other option is to use straight pins to pierce the insulation of the wires. First check the voltage of the outer two wires of the MAP connector by connecting a voltmeter to the clips or pins you have inserted. You should see 5 volts with the key on. This is the power to the sensor. The BLK/WHTwire provides a ground called Signal Return (SIG RTN on EEC), it will show 0 volts with the black probe on negative battery terminal. The 5 volts VREF (ON EEC) (Reference Voltage) is supplied on the ORG/White wire. The Signal the computer reads is on the middle wire, DK BLUE/-Lt GRN (MAP on EEC). The correct MAP range of measurement is typically from 1.4 to 1.6 volts on the Signal (middle wire). If any of the voltages are out of range, there is a wiring problem that needs to be tracked down and repaired. These three wires all go back to the computer. The signal wire (middle) is the only one not shared by other sensors, it goes straight to the computer. The Signal Return and VREF are also provided to other sensors..." Read More
Source: by miesk5 at FSB https://www.fullsizebronco.com/forum/showthread.php?t=202290

DTC 22 & 126 indicates the Manifold Absolute Pressure (MAP) sensor is out of Self-Test range. Correct MAP range of measurement is typically from 1.4 to 1.6 volts. read more


DTC 21 ECT out of self test range 0.3 to 3.7 volts.
DTC 21 ECT out of self test range 0.3 to 3.7 volts; "... ECT is bad, engine not warmed up, bad thermostat, low coolant..Coolant is less than 50 deg F for KOEO, or less than 180 deg F for KOER, or greater than 250 deg F for either. If coolant temp is in proper range, suspect ECT sensor or it's connector/wiring..." read more
Source: by me at FSB https://www.fullsizebronco.com/forum/showthread.php?t=184667

Testing; "..."But due to its simplicity of design, the ECT is rarely at fault when problems occur. Before testing the ECT or any other EFI component perform a self-test, trouble codes received during test can be used as a diagnostic tool along with other indicators. To test an ECT sensor you will need a volt meter. You can test the ECT by back probing the harness while reading the voltage returning to the EEC. Or you can removing the connector completely and test the resistance between the 2 pins on the ECT..." READ MORE Source: by Ryan M at http://www.fuelinjectedford.com/images/eec04.gif

To help in testing; use these by Ryan;
EEC IV 60 PIN CONNECTOR LEGEND @ Ford Fuel Injection


EEC IV 60 Pin Connector Pin Diagram
 
#4 ·
Interesting, my '94 has three digit codes - did you use a code reader, or the paperclip method to read the codes?
 
#6 ·
yo,
Mikey & RLA
Yep! I lost track of the OP's Year;
Ford went from two-digit to three-digit EEC IV Self-Test codes in 1991 to service the increasing number of service codes required to support various government On-Board Diagnostic (OBD) regulations. The phase-in from two-digit to three-digit codes started in the 1991 model year. 96 Broncos have OBD II that has 4 characters beginning with Letter P
 
#9 ·
I think I will start with the simple/cheap solutions first.
21- Get engine up to operating temp before testing
22&23- Replace the Intake and Plenum Gasket, and clean the throttlebody and surrounding
67- Test/replace the Neutral safety switch/MLP
94- Seafoam the trans fluid. Fully flush the trans, to see if it is a blocked TCC solenoid.
87- I'm loosing fuel pressure over night and have to prime the fuel pump before it will start. I will probably just replace pump.

If those don't do it, I can work my way up from there.
 
#11 ·
Try to pull codes again, there are no DTC codes 679 and 487 -
 
#13 ·
#14 ·
OK...I pulled the codes again, and this time it was up to full operating temp. The CEL didn't come on until the idle started fluctuating. It gave me 2223678493. It is not giving enough numbers for 3 digit codes. I ran the test four times and got the same numbers.
 
#15 ·
It would be EXTREMELY rare to have 2 digit codes from your 1994. The theory would be plausible if someone swapped in an older PCM (computer). Either way your codes are not making much sense to me.
 
#16 ·
yo,
As RLA suggested;

Check the Calibration Code on the PCM
Location pic; on PCM in a 95 5.8; with Ford Part Number

by marnefist


Then look at Calibration Label Sticker on driver's door jamb and compare

pic by Seattle FSB (SeattleFSB)
 
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