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Diagnostic Procedures

Follow the sequence given in the following "Diagnostic Charts" until proper problem identification and correction can be made. Refer to appropriate wiring diagrams in this article and other illustrations to assist in diagnosis.

Fig 1: C-4 Wiring Diagram for 1980 4-Cyl., V-6 ("H" Body) and V8 Models

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Fig 2: C-4 Wiring Diagram for 1980 V-6 Models - Except "H" Body

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Fig 3: DIAGNOSTIC CIRCUIT CHECK

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Fig 4: SYSTEM PERFORMANCE CHECK

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Fig 5: DRIVER COMPLAINT OR EMISSION NON-COMPLIANCE

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Fig 6: CHART NO. 1 ALL EXCEPT 3.8L V-6 DWELL FIXED - 5-10°

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Fig 7: CHART NO. 1 3.8L V-6 DWELL FIXED - 5-10°

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Fig 8: CHART NO. 3 DWELL FIXED - 50-55°

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Fig 9: CHART NO. 2 DWELL FIXED - 10-50°

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Fig 10: CHART NO. 4A W.O.T. CIRCUIT CHECK

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Fig 11: CHART NO. 48 T.P.S. CIRCUIT CHECK

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Fig 12: CHART O. 5 "CHECK ENGINE" LIGHT INOPERATIVE

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Fig 13: CHART NO. 6 LEAN LIMIT SWITCH CIRCUIT CHECK

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Fig 14: CHART NO. 8 CLOSED THROTTLE SWITCH CIRCUIT CHECK

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Fig 15: TROUBLE CODE 12 V8 ENGINES

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Fig 16: TROUBLE CODE 12 2.5L 4-CYLINDER & 2.8L V-6 ENGINES

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Fig 17: TROUBLE CODE 13 ALL EXCEPT 5.7L V8 ENGINE

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Fig 18: TROUBLE CODE 12 3.8L V6 ENGINE

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Fig 19: TROUBLE CODE 13 5.7L V8 ENGINE

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Fig 20: TROUBLE CODE 14

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Fig 21: TROUBLE CODE 21 ENGINES EQUIPPED WITH THROTTLE POSITION SENSOR ONLY

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Fig 22: TROUBLE CODE 15

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Fig 23: TROUBLE CODE 21 3.8L V6 ENGINE

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Fig 24: TROUBLE CODE 22 2.5L 4-CYL. ENGINE

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Fig 25: TROUBLE CODE 21 & 22 TOGETHER 2.5L 4-CYL. ENGINE

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Fig 26: TROUBLE CODE 32 OR 32 & 55 TOGETHER EXCEPT 3.8L V-6 ENGINE 4-TERM BARO SENSOR

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Fig 27: TROUBLE CODE 23

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Fig 28: TROUBLE CODE 32 OR 32 & 55 TOGETHER 3.8L V-6 ENGINES 4-TERM BARO SENSOR

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Fig 29: TROUBLE CODE 34 3.8L V6 ENGINE WITH MAP SENSOR

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Fig 30: TROUBLE CODE 44 & TROUBLE CODE 44 & 55 TOGETHER

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Fig 31: TROUBLE CODE 43

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Fig 32: TROUBLE CODE 45

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Fig 33: TROUBLE CODES 51 THRU 54

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Fig 34: TROUBLE CODE 55

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