|
THE CONNECTOR
-----------------------
| 1 2 3 4 5 6 |
| 7 8 9 10 11 12 |
-----------------------
With the ignition OFF, take a paper clip or a small piece of wire and connect pin #6 to pin #12
(on later cars it will be pin #5 to pin #6) then turn on the ignition to the ON position without starting the engine.
The "Service Engine Soon" light will flash in the following sequence:
flash, pause, flash-flash, long pause flash, pause, flash-flash, long pause flash, pause, flash-flash, long pause
To clear all codes from your ECM, disconnect the negative battery cable at the battery and wait about 30 seconds then
reconnect it. If your cars stereo requires you to enter a 4 digit code when you do this,
the best thing for you to do is to just remove the fuse going to the ECM.
Possible Failures Associated with ECM Codes (From most likely to least likely)
Note: Some codes have been deleted because they do not apply to the 1982-1992 Firebird
12:) Diagnostic mode / ECM functioning No reference pulses to ECM.
13:) Oxygen sensor signal problem or loss.
13 Check wiring and connectors. Bad Sensor
14:) Coolant sensor - High temperature fault.
14 Check wiring, connectors, thermostat. Monitor actual engine temperature. If within limits, and wiring/connector is OK, change thermostat and/or sensor.
15:) Coolant sensor - Low temperature fault.
15 See above, particularly thermostat
16:) Battery system over voltage - over 17.1 volts OR Direct ignition system fault.
16 Direct Ignition (DI) Fault
17:) Crank signal circuit shorted (RPM signal problem).
21:) TPS (Throttle position sensor) voltage high.
21 Sticking or Misadjusted TPS. Also check wiring/connectors. Adjust/replace TPS.
22:) TPS (Throttle position sensor) voltage low OR Fuel cutoff relay circuit open or shorted to ground.
22 Sticking or Misadjusted TPS. Also check wiring/connectors. Adjust/replace TPS.
23:) MAT (Manifold Air Temperature) sensor fault - low temperature OR TPS error.
23 Measure sensor resistance with Digital Ohm meter. Must not be 0 ohms or infinite ohms. Replace if it shows one of these readings. Check wiring/connector of
sensor. If OK, replace sensor.
24:) VSS (Vehicle Speed Sensor) circuit fault - loss of signal.
24 Only valid if vehicle moving. Check connections at ECM Check TPS setting.
Possible ECM failure.
25:) MAT (Manifold Air Temperature) sensor fault - high temperature.
25 Measure sensor resistance with Digital Ohm meter. Must not be 0 ohms or infinite ohms. Replace if it shows one of these readings. Check wiring.connector of
sensor OK.
26:) Quad driver module circuit fault (3.8L) OR Throttle switch circuit shorted.
26 Check EGR, Canister Purge and AIR pump relays with a digital Ohm meter. A resistance of less than 18 ohms indicates a bad relay. If OK, potential ECM failure.
27:) Throttle switch circuit open - fault in 2nd gear switch.
27 Potential ECM or on a manual transmission car, potential upshift relay problem.
Check relay, replace if less than 18 Ohms using a digital Ohm Meter.
28:) Fault in 3rd gear switch.
28 Air conditioning Clutch relay and/or cooling fan relays. Check with digital Ohm
meter, replace if less than 18 Ohms. If relays OK, potential ECM failure.
29:) Fault in 4th gear switch.
31:) Turbo over-boost fault OR Canister purge solenoid fault OR Camshaft sensor circuit fault OR EGR circuit fault OR MAP (Manifold Air Pressure) sensor circuit shorted - low voltage OR Fuel injector fault OR Park or neutral switch OR governor malfunction.
32:) MAP (Manifold Air Pressure) sensor circuit open OR EGR fault OR Barometric pressure circuit shorted.
32 The most common cause of this code is a bad or intermittent EGR switch which is
located on the EGR pipe between the exhaust manifold and the intake manifold.
Replace this switch first when you get this code. Next, check electrical
connections at EGR valve solenoid and then the ECM. Check all vacuum lines for
leaks especially around the EGR valve. Possible ECM failure.
33:) MAP (Manifold Air Pressure) sensor voltage low - pressure low/vacuum high OR MAF (Mass Air Flow) sensor signal low - flow high.
33 (1984) Check vacuum hoses. Check wiring to sensor. Change sensor. Check connections at ECM.
(1985-1990) Inspect intake system for leaks, Inspect for vacuum leaks, Check
MAF connector and wiring, Check MAF for open using digital Ohm meter.
Possible ECM failure.
34:) MAP (Manifold Air Pressure) sensor voltage high - pressure high/vacuum low OR MAF (Mass Air Flow) signal high - flow low.
34 (1984) Check Vacuum hoses associated with MAP sensor. Check wiring and
connections, particularly at ECM. Replace the sensor. Possible ECM failure.
(1985-1990) Clean the throttle body. Check MAF connections. Replace MAF
relay. Replace MAF Sensor. Possible ECM failure.
35:) Idle speed cannot be set to desired RPM.
35 Check fuel pressure, injectors, leaking throttle body. Change the IAC valve.
36:) MAF (Mass Air Flow) sensor burn-off circuit failure OR fault in direct ignition system OR Missing pulses in electronic spark timing signal.
36 Check connections at MAF, MAF relay and MAF Burn off relay. Check resistance
of MAF relay and MAF burnoff relay with digital Ohm meter. replace if less than 18
Ohms. Possible ECM failure.
37:) MAT (Manifold Air Temperature) sensor high temperature.
38:) MAT (Manifold Air Temperature) sensor low temperature OR brake input circuit failed (brake light switch) OR fault in torque converter clutch brake switch.
39:) Fault in TCC (Torque Converter Clutch) circuit.
41:) EST (Electronic Spark Timing) circuit failure - no distributor pulses OR cylinder select error OR Tachometer input error.
41 Check wiring at ECM. Possible PROM failure, or incorrectly seated PROM.
Reseat PROM. Possible ECM failure.
42:) EST (Electronic Spark Timing) circuit grounded OR fault at direct ignition system OR fault at fuel cutoff relay. 43:) TPS (Throttle position sensor) out of adjustment OR knock sensor signal error OR low voltage at electronic spark timing control.
42 Check wiring at ignition module. Replace ignition module. Possible ECM failure.
43 Check ECM wiring. Replace knock sensor
44:) Oxygen sensor lean error.
44 Check wiring.connectors at Oxygen sensor. Check fuel pressure. Replace Oxygen sensor.
45:) Oxygen sensor rich error.
45 Check evaporative charcoal canister for smell of fuel (which normally comes from filling fuel tank to full). check fuel pressure regulator. Possible leaking fuel injector or sticking/bad EGR valve. Possible bad Oxygen sensor.
46:) Fault in VATS (Vehicle Anti Theft System) OR fault at power steering switch (4 cylinder).
46 With negative battery lead disconnected and using high pressure, non residue
contact spray cleaner, spray into area where ignition key inserts followed by
inserting and removing key several times. Check for open/short on harness from
steering column VATS ignition key to ECM. Possible defective anti-theft module.
47:) Problem at ECM or ECM failure.
48:) Misfire diagnosis.
49:) MAP (Manifold Air Pressure) sensor low error - vacuum leak.
51:) ECM, PROM, or MEM-CAL failure.
51 Faulty or incorrect PROM in the ECM. Change PROM with correct version for
automobile.
52:) ECM or CALPAK failure OR Analog to digital error OR fault at Quad driver module OR low oil pressure sensor voltage.
52 Check connections at the oil temperature switch. If OK, replace switch.
53:) System over voltage - over 17.1 volts OR EGR sensor fault, improper EGR vacuum OR VATS alert.
53 If voltage is more than 17.1 or less than 10 volts, this code will be set. Check
battery leads, alternator drive belt for tightness and have electrical shop check
alternator output. Voltage with engine off should be 12 volts. Voltage with engine
running should be 14-15 volts. Use digital volt meter for checks and measure at
the battery terminals.
54:) Low voltage at either fuel pump or fuel pump relay OR output failure at quad driver module.
54 Using digital Ohm meter, check fuel pump circuits for shorts or opens.
55:) ECM failure or poor ECM connection OR oxygen sensor failure.
55 This code is set when there is not enough fuel when accelerating. A possible fuel
pump failure or insufficient fuel pressure due to a fuel line restriction is indicated.
56:) Coolant level low OR quad driver B circuit (3.8L).
58:) PASS key fuel enable circuit OR VATS alert.
61:) Oxygen sensor failure OR cruise control vent valve solenoid fault (3.8L).
62:) Cruise control vacuum circuit fault (3.8L).
62 Check wiring associated with Oil temperature switch. Replace switch.
63:) MAP sensor voltage high, low vacuum/open circuit (2.8L) OR EGR flow check (3.8L).
63 Check wiring and connections to Oxygen sensor.
64:) MAP sensor voltage low, high vacuum/short circuit (2.8L) OR EGR flow check (3.8L).
64 Check wiring and connections from Oxygen sensor to ECM. Check ECM ground
terminal and battery ground. Check fuel pressure and fuel pump. Replace Oxygen sensor if all of above OK.
65:) Fuel injection circuit fault OR EGR flow check.
65 Check evaporative charcoal canister for fuel fumes. Replace if contaminated.
Check oil for presence of fuel. Check fuel pressure regulator, fuel pump, check for leaking injectors, Check for stuck/defective EGR valve, Replace Oxygen sensor if
all above OK.
66:) A/C pressure switch low pressure OR internal reset of ECM.
67:) Cruise control switch failure.
68:) Cruise control system fault.
69:) A/C pressure switch high pressure.
88:) ECM fault, internal reset.
108:) PROM checksum error.
Sensor Locations
82 - 92 F-Body
Sensor Location
(CTS) Engine Coolant Temp Sensor. - Front of engine, below Throttle Body.
Engine Oil Temperature Sensor. - Left rear of engine, just above the oil filter.
Oil Pressure Sender/Switch. - Top, left hand rear of engine.
Fuel Quantity Sender. - Top of fuel tank, beneath filler pipe escutcheon panel.
(MAT) Manifold Absolute Temperature Sensor. - Underside of manifold air plenum at rear.
Outside Temperature Sensor. - Right side of engine, top right corner of radiator.
In Car Temp Temperature Sensor. - Coupe: above left seat near interior courtesy light, Convertible: center of cargo compartment lid.
(MAF) Mass Air Flow Sensor. - Front of engine ahead of throttle body.
(O2) Oxygen Sensor. - Left side of engine, in exhaust pipe.
(TPS) Throttle Position Sensor. - Right side of throttle body at the front.
1987 - 1992
1 G 1 F P 2 1 H X H L 1 0 0 0 0 1
| | | | | | | | | | | +---------+---> Production Sequence
| | | | | | | | | | +---------------> Assembly Plant
| | | | | | | | | | N = Norwood (1987 only)
| | | | | | | | | | L = Van Nuys
| | | | | | | | | +-----------------> Model Year
| | | | | | | | | H = 1987
| | | | | | | | | J = 1988
| | | | | | | | | K = 1989
| | | | | | | | | L = 1990
| | | | | | | | | M = 1991
| | | | | | | | | N = 1992
| | | | | | | | +-------------------> Check Digit
| | | | | | | +---------------------> Engine Code
| | | | | | | S = 173 ci V6 LB8 (1987-1989)
| | | | | | | T = 191 ci V6 LH0 (1990-1992)
| | | | | | | F = 305 ci V8 LB9 (1987-1992)
| | | | | | | H = 305 ci V8 LG4 (1987)
| | | | | | | E = 305 ci V8 L03 (1988-1992)
| | | | | | | 8 = 350 ci V8 B2L/L98 (1987-1992)
| | | | | | +-----------------------> Restraint System
| | | | | | 1 = Manual belts
| | | | | | 2 = Manual belts (built in safety)
| | | | | | 3 = Manual belts (driver inflatable)
| | | | | | 4 = Automatic belts
| | | | | +-------------------------> Body Type
| | | | | 2 = 2 door coupe (hatchback)
| | | | | 3 = 2 door convertible
| | | | +---------------------------> Carline Series
| | | | Chevrolet:
| | | | P = Camaro (all models)
| | | | Pontiac:
| | | | S = Firebird
| | | | W = Formula, Trans Am
| | | +-----------------------------> Carline Code
| | | F = F-Body
| | +-------------------------------> Make
| | 1 = Chevrolet
| | 2 = Pontiac
| +---------------------------------> Manufacturer
| G = General Motors
+-----------------------------------> Country
1 = USA
2 = Canada
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