codes 12, 21, 55.
What do 12, 55 actually mean.
11 IGN reference signal.
12 Battery input to PCM disconnected during last 50 key starts.
13 MAP sensor pneumatic circuit.
14 MAP sensor electrical circuit.
15 Vehicle speed/distance sensor.
16 Open or shorted condition detected in knock sensor circuit.
17 Engine running too cool.
21 Oxygen sensor circuit.
22 Coolant temperature sensor circuit.
23 Intake air temp. sensor voltage high.
24 Throttle position sensor.
25 IAC motor driven circuit.
27 Fault in injector driver interface circuit.
31 Purge solenoid circuit.
32 Fault in EGR diagnostics.
34 Speed control solenoid circuits.
33 A/C cutout relay circuit.
35 Fan control relay circuit.
41 Charging system excess or no field current.
42 ASD relay circuit.
43 Fault in ignition coil control circuit.
44 Battery Temp Voltage.
45 Overdrive Solenoid open or shorted
46 Battery voltage too high.
47 Battery voltage too low.
51 Oxygen feedback system stuck at lean position.
52 Oxygen feedback system stuck at rich position.
53 Internal logic module problems.
54 No cam position signal.
55 Completion of fault code display.
62 Indicates unsuccessful attempt to update EMR mileage.
63 Unsuccessful attempt to write to an EEPROM location by the controller.
64 Methanol sensor voltage too low.