Engine Control Module (ECM) Connectors

WARNING: This page is about a different car, the 2004 GMC Sierra, 2004 GMC Cab & Chassis Sierra, 2004 Chevrolet Silverado, and 2004 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.

Engine Control Module (ECM) - C1

Courtesy of GENERAL MOTORS CORP.
Connector Part Information		12191489 80-Way F Micro-Pack 100W Sealed (BLU)
Pin	Wire Color	Circuit No.	Function
1	BLK/WHT	451	Ground
2	LT GRN	1867	12 Volt Reference
3	BLK	1744	Fuel Injector 1 Control
4	LT BLU/BLK	844	Fuel Injector 4 Control
5	TAN/WHT	332	Oil Pressure Sensor Signal
6	BRN	1456	EGR Vacuum Sensor Signal - w/California Emissions Only
7	YEL/BLK	975	5 Volt Reference
8	GRY	2705	5 Volt Reference
9	DK GRN	2362	SAE J1939 Serial Data Bus -
10	YEL	2361	SAE J1939 Serial Data Bus+
11	-	-	Not Used
12	LT BLU/WHT	1869	CKP Sensor Signal
13 - 16	-	-	Not Used
17	YEL/BLK	508	Water In Fuel Indicator Control
18	DK BLU	84	Cruise Control Set/Coast Switch Signal
19	PNK	439	Ignition 1 Voltage
20	ORN	440	Battery Positive Voltage
21	YEL/BLK	1868	Low Reference
22	GRY/BLK	87	Cruise Control Resume/Accel Switch Signal
23-24	-	-	Not Used
25	ORN/BLK	469	Low Reference
26 -28	-	-	Not Used
29	TAN	986	Intake Heater Diag 1
30	LT GRN	1478	Coolant Level Switch Signal
31	-	-	Not Used
32	BRN	2524	Generator 2 Turn On Signal
33	PPL	806	Crank Voltage
34	ORN/BLK	1786	Park/Neutral Signal
35	GRY	48	CPP Switch Signal
36	LT GRN/BLK	1745	Fuel Injector 2 Control
37	BLU/WHT	845	Fuel Injector 5 Control
38 -39	-	-	Not Used
40	BLK/WHT	451	Ground
41	BRN	971	Low Reference
42	-	-	Not Used
43	DK BLU/WHT	878	Fuel Injector 8 Control
44	PNK/BLK	1746	Fuel Injector 3 Control
45	TAN	1274	5 Volt Reference
46	WHT/BLK	2932	5 Volt Reference
47	WHT/BLK	1164	5 Volt Reference
48	TAN	2917	5 Volt Reference
49 -51	-	-	Not Used
52	LT BLU	506	Glow Plug Signal
53	-	-	Not Used
54	PPL	1272	Low Reference
55	LT BLU	1162	APP Sensor 2 Signal
56	-	-	Not Used
57	ORN	440	Battery Positive Voltage
58	DK GRN	1049	Class 2 Serial Data
59	YEL	710	Class 2 Serial Data
60	-	-	Not Used
61	PNK/BLK	632	Low Reference
62	LT GRN	1324	Backup Lamp Supply Voltage
63	-	-	Not Used
64	BLK	552	Low Reference
65	GRY	1273	Low Reference
66 -69	-	-	Not Used
70	BRN	1174	Oil Level Switch Signal
71	LT GRN	488	PTO Enable
72	-	-	Not Used
73	BRN/WHT	633	CMP Sensor Signal
74	YEL	410	ECT Sensor Signal
75	PNK	1020	Off/Run/Crank Voltage
76	YEL/BLK	846	Fuel Injector 6 Control
77	RED/BLK	877	Fuel Injector 7 Control
78	PPL	985	IA Heater Relay Control
79	GRY/BLK	2219	FICM Relay Control
80	GRY	720	Low Reference

Engine Control Module (ECM) - C2

Courtesy of GENERAL MOTORS CORP.
Connector Part Information		12191488 80-Way F Micro-Pack 100W Sealed (CLR)
Pin	Wire Color	Circuit No.	Function
1	BLK/WHT	451	Ground
2	WHT	257	EGR Valve Vacuum Solenoid Control - w/California Emissions Only
3-5	-	-	Not Used
6	YEL	505	Glow Plug Relay Control
7 -8	-	-	Not Used
9	DK GRN/WHT	465	Fuel Pump Relay Control
10	WHT	121	Engine Speed Signal
11	DK BLU	604	A/C High Pressure Recirculation Switch Signal
12	DK GRN	1163	APP Sensor 3 Signal
13	YEL	2522	PTO Feedback Status
14	LT GRN	432	Boost Sensor Signal
15	BRN	25	Charge Indicator Control
16	GRY	397	Cruise Control On Switch Signal
17	DK GRN/WHT	2523	A/C Request Signal
18	LT BLU	1320	CHMSL Supply Voltage
19	BLK/WHT	1695	Axle Switch Signal
20	LT GRN/BLK	822	VSS Low Signal (Except Allison
21	PPL/WHT	821	VSS High Signal (except Allison)
21	YEL	400	Signal High - Front - Allison Transmission
22	-	-	Not Used
23	ORN/BLK	2919	Low Reference
24	DK BLU	1161	APP Sensor 1 Signal
25	YEL	1578	Fuel Temperature Signal
26 -28	-	-	Not Used
29	GRY	597	5 Volt Reference
30 -32	-	-	Not Used
33	DK GRN	1614	Recirculation Door Control
34	DK GRN/WHT	459	A/C Compressor Clutch Relay Control
35	PNK/WHT	1101	Damping Lift/Dive Signal
36	DK BLU	507	Wait to Start Indicator Control
37	PPL	2562	PTO Engage Signal
38	-	-	Not Used
39	RED	631	12 Volt Reference
40	BLK/WHT	451	Ground
41	GRY/BLK	2931	Low Reference
42	PPL/WHT	2530	Fuel Pressure Regulator Solenoid Supply Voltage
43	-	-	Not Used
44	PNK	1039	Ignition 1 Voltage
45	-	-	Not Used
46	BRN/WHT	419	MIL Control
47	DK GRN/WHT	428	EGR Throttle Valve Vacuum Solenoid Control - w/California Emissions Only
48	WHT	1310	EGR Vacuum Vent Solenoid Control - w/California Emissions Only
49	YEL/BLK	1827	Vehicle Speed Signal
50	DK GRN/WHT	817	Vehicle Speed Signal
51	TAN	472	IAT Sensor Signal
52	GRY	23	Generator Field Duty Cycle Signal
53	DK BLU	2687	TCM MIL Request
54	PPL/WHT	1589	Fuel Level Sensor Signal - Primary
55	DK GRN	603	A/C Low Pressure Switch Signal
56	LT BLU	494	PTO Engine Disable
57	ORN/BLK	510	Low Reference
58	YEL	2918	FRP Sensor Signal
59	PPL	420	TCC Brake Switch/Cruise Control Release Signal
60	BRN	718	Low Reference
61	-	-	Not Used
62	TAN	986	Intake Heater Diag 2
63	GRY/BLK	1694	4WD Low Signal
64	GRY/BLK	433	BARO Sensor Signal
65	YEL	492	MAF Sensor Signal
66 -72	-	-	Not Used
73	DK BLU	1936	Fuel Level Sensor Signal - Secondary
74-75	-	-	Not Used
76	LT BLU	2832	Engine Speed Signal
77	YEL	2834	Fuel Pressure Regulator Solenoid Control
78	ORN/BLK	1057	Low Reference
79 -80	-	-	Not Used