Early 90's mopars used the check engine light and cycling the ignition switch to dump the codes. It worked on my dad's 91 wrangler. On off on off on with the key and the codes should dump, here is a list of them: DTC No. Scan Tool Display Description of Conditions 11 (1) No reference signal during cranking No camshaft reference signal detected during engine cranking. 12 (1) Battery disconnect Battery input to PCM disconnected during last 50 key starts. 13 (2) No change in MAP from start to run No variation in MAP sensor is detected No difference recognized between engine MAP reading and barometric pressure reading at start-up. 14 (2) MAP voltage too low Map sensor input below minimum acceptable voltage. or MAP voltage too high Map sensor input above maximum acceptable voltage. 15 (2) No vehicle speed signal No vehicle distance (speed) sensor signal detected during road load conditions. 17 (1) Engine is cold too long Engine coolant temperature remains below normal operating temperatures during vehicle travel (thermostat). 21 (2) O2 sensor voltage at center Neither rich or lean condition is detected from the oxygen sensor input. or O2 sensor voltage high Oxygen sensor input voltage maintained above normal operating range. 22 (2) ECT sensor voltage low Sensor input below the minimum acceptable voltage. or ECT sensor voltage high Sensor input above the maximum acceptable voltage. 23 (2) Intake air temp. sensor voltage high Sensor input above the maximum acceptable voltage. or Intake air temp. sensor voltage low Sensor input below the minimum acceptable voltage. 24 (2) TPS voltage low Sensor input below the minimum acceptable voltage. or TPS voltage high Sensor input above the maximum acceptable voltage. 25 (2) IAC motor circuits An open or shorted condition detected in one or more of the IAC control circuits. 27 (2) Injector #1 control circuit Injector output driver does not respond properly to the control signal. or Injector #2 control circuit Injector output driver does not respond properly to the control signal. or Injector #3 control circuit Injector output driver does not respond properly to the control signal. or Injector #4 control circuit Injector output driver does not respond properly to the control signal. or Injector #5 control circuit Injector output driver does not respond properly to the control signal. or Injector #6 control circuit Injector output driver does not respond properly to the control signal. 33 (1) A/C clutch relay circuit An open or shorted condition detected in the A/C clutch relay circuit. 34 (1) Speed Control solenoid circuits An open or shorted condition detected in the speed control vacuum or vent solenoid circuits. 35 (1) Rad Fan Control relay Circuit An open or shorted condition detected in the radiator fan relay circuit. 41 (2) Generator field circuit An open or shorted condition detected in the generator field control circuit. 42 (1) ASD relay control circuit An open or shorted condition detected in the auto shut down relay circuit. or No ASD voltage sense No ASD voltage sensed at PCM. 44 (1) Battery temp. voltage Battery temperature sensor volts out of range. 46 (2) Charging voltage high Battery voltage sense input above target charging voltage during engine operation. 47 (2) Charging voltage low Battery voltage sense input below target charging voltage during engine operation. 51 (2) Lean O2 signal Oxygen sensor signal indicates lean fuel/air ratio condition during engine operation. or Adaptive memory rich Added adaptive memory at rich limit. 52 (2) Rich O2 condition Oxygen sensor signal indicates rich fuel/air ratio condition during engine operation. or Adaptive memory lean Added adaptive memory at lean limit. 53 (1) PCM failure Internal PCM fault detected. 54 (1) No cam signal No fuel sync (cam position) signal detected during crankshaft rotation. 55 (1) Display not shown on scan tool Completion of fault code display on Malfunction Indicator Lamp (Check Engine Lamp) 62 (1) PCM failure PCM failure SRI miles not stored SRI miles not stored 63 (1) PCM failure PCM failure EEPROM write denied EEPROM write denied -----Original Message----- From: Mark Price [mailto:mprice@xxxxxxxxxx] Sent: Sunday, May 29, 2005 9:22 PM To: mail@xxxxxxxxxxxx Cc: AMC-DelMarVA@xxxxxxxxxxxxxxx; mail@xxxxxxxxxxxx Subject: success! It's legal and on the road again! I had to do several circling procedures and play phone tag with Hagertys, but the insurance was in place last night and today I actually drove the American on it's maiden voyage! Not too far, just a few miles to get a feel for things. It is much better then before. I can drive it and shift gears with no lurching and hesitation, My knees don't hit the steering wheel now that it has tilt either! I do have an intermittant check engine light. Is there a way to get a code out of a 91 H.O system without a code reader? I'm a pretty sure it's full throttle power is down from the 4 barrel setup , but the driveability is awesome! I have some little things to go over before I start putting any serious miles on it. Nothing too serious though. I'm just plain glad to finally get it to this point!!! Mark Price mprice@xxxxxxxxxx Morgantown, WV 69 AMC rambler, 4.0L, EFI, 5 speed 65 Ambassador Conv, 327 AUTO, Basketcase