Pontiac Firebird 3.4L – Grand AM 3.1L – Grand Prix 3.1L (1993 – 1995) Trouble Code Info

Model Year Engine identification System
Firebird 3.4L 1993-95 VIN  position 8 = S GM
Grand AM  3.1 L 1994-95 VIN  position 8 = M GM
Grand Prix 3.1 L 1994-95 VIN  position 8 = T/M GM

General information

  • Refer to the front of this manual for general test conditions, terminology, detailed descriptions of wiring faults and a general trouble shooter for electrical and mechanical faults.
  • Malfunction indicator lamp (MIL) will illuminate if certain faults are recorded.
  • ECM operates in backup mode if sensors fail, to enable vehicle to be driven to repair shop.
  • Trouble codes can be displayed by the MIL or by using a Scan Tool connected to the data link connector (DLC).
Firebird-prix1Firebird-prix2

Accessing

Models with data link connector (OLe) terminal B connected

  • Access data link connector (DLC).
  • Jump data link connector (DLC) terminals A and B [1].
  • Switch ignition ON. Do NOT start engine.
  • Count MIL flashes. Note trouble codes. Compare with trouble code table.
  • Firstly trouble code 12 will be displayed 3 times.
  • Trouble codes consist of 2 groups, displayed as follows:
  • First group indicates the ‘tens’ of the trouble code [2] [A].
  • Second group indicates the ‘units’ of the trouble code [2] [C].
  • A short pause separates each group [2] [B].
  • A long pause separates each trouble code [2] [D).
  • For example: Trouble code 12 displayed fl. Start of diagnosis.
  • Each additional trouble code will now be displayed 3 times, in ascending order.
NOTE: If no additional trouble codes are stored, code 12 will continue to be displayed.
  • Trouble codes can also be displayed by using a Scan Tool connected to the data link connector (DLC) 1

Models without data link connector (DLC) terminal 8 connected

• Trouble codes can only be displayed by using a Scan Tool connected to the data link connector (DLC) 1.

Erasing

NOTE: Disconnecting battery ground lead may cause driveabi/ity problems until the engine management system relearns basic values.
  • Ensure ignition switched OFF.
  • Disconnect battery ground cable for 30 seconds.
  • Reconnect battery ground cable .
  • Repeat checking procedure to ensure no trouble codes remain in ECM fault memory.
NOTE: Disconnecting battery ground lead may also erase memory from electronic units, such as radio.
• Trouble codes can also be erased by using a Scan Tool connected to the data link connector (DLC) 1.

Trouble code  identification

Flash code Fault location Probable cause
12 Start of diagnosis No engine speed (RPM) signal received
13 D Heated oxygen sensor (H02S) Wiring open circuit, H02S, ECM
13 f) Oxygen sensor (028), bank 2 Wiring open circuit, 02S, ECM
14 Engine coolant temperature (ECT) sensor voltagelow Wiring short circuit to ground, ECT sensor, ECM
15 Engine coolant temperature (ECT) sensor voltagehigh Wiring open circuit, ECT sensor, ECM
16 System voltage low Wiring, alternator
17 Camshaft position (CMP) sensor -circuit malfunction Wiring, CMP sensor, mechanical fault, ECM
21 Throttle position (TP) sensor -voltage high Wiring open circuit/short circuit to positive, TP sensor, ECM
22 Throttle position (TP) sensor -voltage low Wiring open circuit/short circuit to ground, TP sensor,ECM
23 Intake air temperature (IAT) sensor -voltage high Wiring open circuit, IAT sensor, ECM
24 Vehicle speed sensor (VSS) -no signal Wiring, VSS, ECM
25 Intake air temperature (IAT) sensor -voltage low Wiring short circuit to ground, IAT sensor, ECM
28 Transmission range (TR) switch -malfunction Wiring, TR switch, ECM
33 Manifold absolute pressure (MAP) sensor voltage high Wiring short circuit to positive, hose blockedl leaking, MAP sensor, ECM
34 Manifold absolute pressure (MAP) sensor voltagelow Wiring open circuit/short circuit to ground, MAP sensor, ECM
35 Idle air control (lAC) valve Wiring open circuit/short circuit to groundl short circuit to positive, lAC valve, intake system leaking,fuel system, PCV valve, AlC system, mechanical fault, ECM
36 Crankshaft position (CKP) sensor, at crankshaft pulley -24X signal circuit malfunction Wiring, CKP sensor, ECM
37 Brake pedal position (BPP) switch for torque converter clutch (TCC) Wiring, incorrectly adjusted, BPP switch, ECM
39 Clutch pedal position (CPP) switch Wiring, incorrectly adjusted, CPP switch, ECM
41 Ignition control. timing signal -circuit malfunction Wiring, poor connections, ICM, ECM
42 Ignition control. bypass signal -circuit malfunction Wiring, poor connections, ICM, ECM
43 Knock sensor (KS) -circuit malfunction Wiring, K5, ECM
44 1 Heated oxygen sensor (H028) mixture lean Wiring open circuit/short circuit to ground, injector(s)blocked, fuel contamination, fuel pressure low,exhaust system leaking, H025, ECM
44 2 Oxygen sensor (028). bank 2 -mixture lean Wiring open circuit/short circuit to ground, injector(s) blocked, fuel contamination, fuel pressure low,exhaust system leaking, 025, ECM
45 1 Heated oxygen sensor (H02S) -mixture rich Wiring open circuit, fuel pressure high, injector(s) leaking, H025, EVAP purge valve, throttle position (TP) sensor, EGR system, ECM
45 2 Oxygen sensor (028). bank 2 -mixture rich Wiring open circuit, fuel pressure high, injector(s) leaking, 025, EVAP purge valve, throttle position (TP) sensor, EGR system, ECM
46 Immobilizer system. code -malfunction Incorrect key, immobilizer control module, ECM
51 Engine control module (ECM). PROM malfunction Poor connections, incorrect programming, ECM
53 System voltage high Alternator
54 Fuel pump circuit -voltage low Wiring open circuit/short circuit to ground, fuel pump relay, engine oil pressure warning lamp/ fuel pump switch
58 Transmission fluid temperature (TFT) sensorvoltage low Wiring short circuit to ground, TFT sensor, ECM
59 Transmission fluid temperature (TFT) sensorvoltage high Wiring open circuit, TFT sensor, ECM
61 AlC system -performance Refrigerant low, wiring, AlC refrigerant pressure sensor, AlC evaporator temperature sensor, ECM
63 Oxygen sensor (028). bank 1 Wiring open circuit, 025, ECM
64 Oxygen sensor (028). bank 1 -mixture lean Wiring open circuit/short circuit to ground, injector(s) blocked, fuel contamination, fuel pressure low,exhaust system leaking, 025, ECM
65 Oxygen sensor (02S). bank 1 -mixture rich Wiring open circuit, fuel pressure high, injector(s) leaking, 025, EVAP purge valve, throttle position (TP) sensor, EGR system, ECM
66 AlC refrigerant pressure sensor -voltage low Wiring open circuit/short circuit to ground, AlC refrigerant pressure sensor, ECM
67 AlC refrigerant pressure sensor -circuit malfunction Wiring open circuit, AlC refrigerant pressure sensor,ECM
68 AlC compressor clutch relay -circuit malfunction Wiring short circuit, AlC compressor clutch relay, ECM
69 AlC compressor clutch relay -circuit malfunction Wiring open circuit, AlC compressor clutch relay, ECM
70 AlC refrigerant pressure sensor -voltage high Wiring open circuit/short circuit to positive, AlCrefrigerant pressure sensor, ECM
71 AlC evaporator temperature sensor -voltage high Wiring, poor connections, AlC evaporator temperaturesensor
72 Vehicle speed sensor (VSS) -circuit malfunction Wiring, VSS, ECM
73 AlC evaporator temperature sensor -voltage low Wiring, poor connections, AlC evaporator temperature sensor
75 Exhaust gas recirculation (EGR) solenoid 1 circuit malfunction Wiring, EGR valve, ECM
76 Exhaust gas recirculation (EGR) solenoid 2 circuit malfunction Wiring, EGR valve, ECM
77 Exhaust gas recirculation (EGR) solenoid 3 circuit malfunction Wiring, EGR valve, ECM
79 Transmission fluid temperature (TFT) high Transmission mechanical fault, towing weight limitexceeded
80 Torque converter clutch (TCC) -slipping Wiring, TCC solenoid, transmission mechanical fault,ECM
81 Brake pedal position (BPP) switch, torque converter clutch (TCC) -circuit malfunction Wiring, BPP switch, ECM
82 Crankshaft position (CKP) sensor, in cylinder block-3X signal circuit malfunction Wiring open circuit/short circuit to ground, CKP sensor, ICM
85 Engine control module (ECM), PROM malfunction Poor connections, incorrect programming, ECM
86 Engine control module (ECM) -analogue/digital converter AlC refrigerant pressure sensor/knock sensor(KS)/engine coolant temperature (ECT) sensor/ fuel pump monitor circuit short circuit to battery voltage
87 Engine control module (ECM), EEPROM malfunction Poor connections, incorrect programming, ECM
90 Torque converter clutch (TCC) -stuck ON Wiring open circuit/short circuit to ground, transmission internal wiring, TCC solenoid, transmission mechanical fault, ECM
93 Transmission fluid pressure (TFP) control solenoid -circuit malfunction Wiring, poor connection, TFP solenoid
96 Engine control module (ECM) -ignition supply voltage low Wiring open circuit, alternator, ECM
98 Engine control module (ECM) -incorrectly coded ECM incorrectly coded, ECM
99 Engine control module (ECM) -incorrectly coded ECM incorrectly coded, ECM