Trouble Codes

These codes are only valid for 1982-1988 Eagles. There were 2 systems used; the GM C-4 was used on the 4-151 engine, and the CCC was used on the 6-258.

I may not be correct that the CCC system was used on the 6-258. I'll update this section as soon as I know.

New: ECM troubleshooting information.

Trouble Code	Applicable System	Notes	Possible Problem Area
12	C-4, CCC		No tachometer or reference signal to computer (ECM). This code will only be present while a fault exists, and will not be stored if the problem is intermittent.
13	C-4, CCC		Oxygen sensor circuit. The engine must run for about 5 minutes at part throttle (and under road load-CCC equipped cars) before this code will show.
13 & 14 (at the same time)	C-4		See code 43.
14	C-4, CCC		Shorted coolant sensor circuit. The engine has to run 2 minutes before this code will show.
15	C-4, CCC		Open coolant sensor circuit. The engine has to operate for about 5 minutes at part throttle (some models) before this code will show.
21	C-4		Shorted wide open throttle switch and/or open closed-throttle switch circuit (when used.)
21	C-4, CCC		Throttle position sensor circuit. The engine must be run up to 10 seconds (25 seconds-CCC system) below 800 rpm before this code will show.
21 & 22 (at the same time)	C-4		Grounded wide open throttle switch circuit.
22	C-4		Grounded closed throttle or wide open throttle switch circuit.
23	C-4, CCC		Open or grounded carburetor mixture control (M/C) solenoid circuit.
24	CCC		Vehicle speed sensor (VSS) circuit. The car must operate up to 5 minutes at road speed before this code will show.
32	C-4, CCC		Barometric pressure sensor (BARO) circuit output low.
32 & 55 (at the same time)	C-4		Grounded +8V terminal or V(REF) terminal for barometric pressure sensor (BARO), or faulty ECM computer.
34	C-4		Manifold absolute pressure (MAP) sensor output hign (after 10 seconds and below 800 RPM).
34	CCC		Manifold absolute pressure (MAP) sensor circuit or vacuum sensor circuit. The engine must run up to 5 minutes below 800 RPM before this code will set.
35	CCC		Idle speed control (ISC) switch circuit shorted (over 1/2 throttle for over 2 seconds).
41	CCC		No distributor reference pulses to the ECM at specified engine vacuum. This code will store in memory.
42	CCC		Electronic spark timing (EST) bypass circuit grounded.
43	C-4		Throttle position sensor adjustment (on some models, engine must run at part throttle up to 10 seconds before this code will set).
44	C-4, CCC		Lean oxygen sensor indication. The engine must run up to 5 minutes in closed loop (oxygen sensor adjusting carburetor mixture), at part throttle and under road load (drive car) before this code will set.
44 & 55 (at the same time)	C-4, CCC		Faulty oxygen sensor circuit.
45	C-4, CCC	Restricted air cleaner can cause code 45.	Rich oxygen sensor system indication. The engine must run up to 5 minutes in a closed loop (oxygen sensor adjusting carburetor mixture), at part throttle under road load before this code will set.
51	C-4, CCC		Faulty calibration unit (PROM) or improper PROM installation in electronic control module (ECM). It takes up to 30 seconds for this code to set.
52 & 53	C-4		"Check Engine" light off: Intermittent ECM computer problem. "Check Engine" light on: Faulty ECM computer (replace).
52	C-4, CCC		Faulty ECM computer.
53	CCC		Faulty ECM computer.
54	C-4, CCC		Faulty mixture control solenoid circuit and/or faulty ECM computer.
55	C-4		Faulty throttle position sensor or ECM computer. Faulty ECM computer.
55	CCC		Grounded +8 volt supply (terminal 19 of ECM computer connector), grounded 5 volt reference (terminal 21 of ECM computer connector), faulty oxygen sensor circuit or faulty ECM computer.

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