To display codes cycle the ignition key On-Off-On-Off-On within three seconds. Check engine light will start to flash - Count the number of flashes, first digit, pause then second digit will be displayed in a series of flashes. (2 flashes, pause, 1 flash = 21)
11 - No Crank Reference Signal At PCM (Crankshaft Position Sensor)
12 - Battery Disconnected Within last 50 Key-on cycles
13 - No Change In MAP Sensor
14 - MAP Voltage Too Low Or Too High
15 - No Vehicle Speed Sensor Signal
17 - Engine Is Cold Too Long
21 - O2 Sensor Signal At Center Or Signal Shorted To Voltage
22 - ECT Sensor Voltage Too Low Or Too High (ECT = Engine Coolant Sensor)
23 - Charge Air Temperature Sensor Voltage Too High Or Low (Intake Air Temp Sensor)
24 - Throttle Position Sensor Voltage Too High Or Too Low
25 - Idle Air Control Motor Circuit Shorted
27 - Injector Control Circuit Signal Not Responding Correctly.
31 - EVAP Purge Solenoid Circuit Open Or Shorted
32 - EGR System Failure
33 - A/C Clutch Relay Circuit Open Or Shorted
34 - Speed Control Solenoid Ciruit Open Or Shorted (Vacuum Or Vent)
37 - Torque Converter Clutch Solenoid Circuit Open Or Shorted
41 - Generator Field Not Switching Properly
42 - Auto Shutdown Relay Control Circuit Open Or Shorted Or No ASD Voltage
44 - Battery Temp Sensor Voltage Out Of Limit
45 - Overdrive Solenoid Circuit Open Or Shorted
46 - Charging System Voltage Too High
47 - Charging SYstem Voltage Too Low
51 - O2 Sensor Signal Stays Below Center (Lean)
52 - O2 Sensor Signal Stays Above Center (Rich)
53 - Internal PCM Failure
54 - Sync Pick-Up Signal Not Detected (Camshaft Position Sensor/Ignition Pickup)
62 - PCM Failure SRI Miles Not Stored
63 - PCM Failure EEProm Write Denied
55 End Of Codes
These codes are good for years 93, 94 and 95.
The above procedure will work for 96 and up but be aware an OBD II scanner will be needed as the above codes could have multiple meanings.
I have seen a few threads asking for this and the link in the faq is not working.
Transmission codes for 42re and mabye others, same routine but displayed via the overdrive light.
11 - Engine RPM Input
12 - Output shaft sensor input
13 - Vehicle speed input
14 - Governor pressure sensor input
15 - Throttle position sensor input
16 - Transmission fluid temp input
17 - Overdrive override switch input
18 - System voltage
19 - Internal fault in module
21 - Governor pressure solenoid output
22 - Overdrive solenoid output
23 - Converter clutch solenoid output
24 - Overdrive override lamp output
25 - Internal fault in module
26 - Governor pressure sensor offset drift
55 - end of codes