GM Service Manual Online
For 1990-2009 cars only

Name

Location

Locator View

Connector End View

Alternative Fuel Engine Control Unit (AF ECU)

LH of the Engine Compartment, in front of the Brake Master Cylinder

Engine Controls Component Views

--

Fuel Pressure Sensor (FPS)

LH front of the pickup box on end of CNG fuel tank

Engine Controls Component Views

--

Fuel Temperature Sensor (FTS)

LH front of the pickup box on end of CNG fuel tank

Engine Controls Component Views

--

Fuel Gauge Relay

LH of the Engine Compartment, under the VCM at the CNG fuse/relay center

Engine Controls Component Views

--

Fuel Gauge Selector Switch/Fuel Indicator Lamp

Bottom center of the IP

Engine Controls Component Views

--

Fuel Pump Relay

LH of the Engine Compartment, under the VCM at the CNG fuse/relay center

Engine Controls Component Views

--

Gas Mass Sensor and Mixture Control Valve (GMS/MCV)

RH front of the Engine

Engine Controls Component Views

--

High Pressure Lock-Off (HPL)

LH front of the pickup box on end of CNG fuel tank

Engine Controls Component Views

--

Ignition Relay

LH of the Engine Compartment, under the VCM at the CNG fuse/relay center

Engine Controls Component Views

--

Lock-Off Relay

LH of the Engine Compartment, under the VCM at the CNG fuse/relay center

Engine Controls Component Views

--

Low Pressure Lock-Off (LPL)

RH middle of the Engine

Engine Controls Component Views

--

C001

LH of the Engine Compartment at the AF ECU (Blue 32-Way)

Engine Controls Component Views

Engine Controls Connector End Views

C002

LH of the Engine Compartment at the AF ECU (White/Clear 32-Way)

Engine Controls Component Views

Engine Controls Connector End Views

C004

LH of the Engine Compartment under the VCM in the CNG fuse/relay center at the Ignition Relay

Engine Controls Component Views

Engine Controls Connector End Views

C007

LH of the Engine Compartment under the VCM in the CNG fuse/relay center at the AF Fuel Pump Relay

Engine Controls Component Views

Engine Controls Connector End Views

C010

RH front of the Engine at the GMS

Engine Controls Component Views

Engine Controls Connector End Views

C011

LH of the Engine Compartment under the VCM in the CNG fuse/relay center at the Lock-Off Relay

Engine Controls Component Views

Engine Controls Connector End Views

C012

LH of the Engine Compartment under the VCM in the CNG fuse/relay center at the Fuel Gauge Relay

Engine Controls Component Views

Engine Controls Connector End Views

C014

RH middle of the Engine at the LPL

Engine Controls Component Views

Engine Controls Connector End Views

C017

LH rear of the Engine Compartment near the Brake Booster (Gray 10-Way)

Engine Controls Component Views

Engine Controls Connector End Views

C018

LH rear of the Engine Compartment near the Brake Booster (Black 10-Way)

Engine Controls Component Views

Engine Controls Connector End Views

C019

LH rear of the Engine Compartment near the Brake Booster (Black 6-Way)

Engine Controls Component Views

Engine Controls Connector End Views

C021

RH front of the Engine at the MCV

Engine Controls Component Views

Engine Controls Connector End Views

C212

Center of the IP at the Cargo Lamp Switch

Engine Controls Component Views

Engine Controls Connector End Views

C239

Center of the IP at the Fuel Gauge Select switch

Engine Controls Component Views

Engine Controls Connector End Views

C313

LH front of the pickup box on end of CNG fuel tank at the HPL

Engine Controls Component Views

Engine Controls Connector End Views

C315

LH front of the pickup box on end of CNG fuel tank at the Fuel Pressure Sensor

Engine Controls Component Views

Engine Controls Connector End Views

C316

LH front of the pickup box on end of CNG fuel tank at the Fuel Temperature Sensor

Engine Controls Component Views

Engine Controls Connector End Views

G103

RH front of the Engine, near the Thermostat Housing

Engine Controls Component Views

--

P001

LH rear of the Engine Compartment at the Bulkhead

--

--

P301

LH floor of the pickup box

--

--

S001

AF Harness, approximately 12.5 cm (4.92 in) from the relay Breakout, toward the AF ECU connector Breakout

--

--

S002

AF Harness, approximately 11 cm (4.3 in) from the fuel pump/IP connector Breakout, toward the 10-way connector Breakout

--

--

S003

AF Harness, approximately 22.5 cm (8.86 in) from the relay Breakout, toward the AF ECU connector Breakout

--

--

S004

AF Harness, approximately 32.5 cm (12.80 in) from the relay Breakout, toward the AF ECU connector Breakout

--

--

S005

AF Harness, approximately 13 cm (5.1 in) from the 10-way connector Breakout, toward the tank connector Breakout

--

--

S009

AF Harness, approximately 20 cm (7.9 in) from the thermostat housing ground stud

--

--

S010

AF Harness, approximately 16.5 cm (6.3 in) from the LPL Breakout, toward the LPL connector

--

--

S011

AF Harness, approximately 11 cm (4.3 in) from the LPL Breakout, toward the LPL connector

--

--

S012

Engine Harness, approximately 6.5 cm (2.56 in) from the Starter Solenoid Breakout, toward the Ignition Coil Breakout

--

--

S013

Engine Harness, approximately 13 cm (5.1 in) from the Starter Solenoid Breakout, toward the Ignition Coil Breakout

--

--

S014

Engine Harness, approximately 6.5 cm (2.56 in) from the Underhood Lamp Connector Breakout, toward the engine

--

--

S015

Engine Harness, approximately 13 cm (5.1 in) from the Underhood Lamp Connector Breakout, toward the engine

--

--

S016

Engine Harness, approximately 6.5 cm (2.56 in) from the Crank Position Sensor Breakout, toward the Crank Position Sensor

--

--

S017

Engine Harness, approximately 13 cm (5.1 in)from the Crank Position Sensor Breakout, toward the Crank Position Sensor

--

--

S018

Engine Harness, approximately 14 cm (5.5 in) into the Thermostat Ground Stud Breakout

--

--

S019

Engine Harness, approximately 10 cm (3.9 in) into the Thermostat Ground Stud Breakout

--

--

S020

Engine Harness, approximately 4 cm (1.6 in) from the Fuse-Relay Center Breakout, toward the Engine

--

--

S021

Engine Harness, approximately 19.5 cm (7.68  in) from the Fuse-Relay Center Breakout, toward the VCM

--

--

S022

Engine Harness, approximately 13 cm (5.1 in) from the Fuse-Relay Center Breakout, toward the VCM

--

--

S023

Engine Harness, approximately 26 cm (10.2 in) into the VCM connector Breakout

--

--

S025

Engine Harness, approximately 25.5 cm (10.04 in) into the Underhood Fuse/Relay Center Breakout

--

--

S030

Engine Harness, approximately 14 cm (5.5 in) from the VCM connector

--

--

S031

Early Production

Engine Harness, approximately 14 cm (5.5 in) from the VCM connector

--

--

S031

Late Production

Engine Harness, approximately 17 cm (6.69 in) from the Underhood Fuse/Relay Center Breakout towards the engine

--

--

S106

Engine Harness, approximately 17 cm (6.69 in) from the EGR valve breakout, toward the fuel injectors breakout

--

--

S271

AF Harness, approximately 10 cm (3.9 in) from the cargo lamp switch

--

--

S276

AF Harness, approximately 10.5 cm (4.0 in) from the fuel selector switch

--

--

S397

AF Harness, approximately 20 cm (7.8 in) from the pickup box grommet, underbody

--

--

S398

AF Harness, approximately 16.5 cm (6.3 in) from the HPL connector inside the pickup box

--

--

S399

AF Harness, approximately 10 cm (3.9 in) from the HPL connector inside the pickup box

--

--

AF D1 (DIODE)

AF Harness, approximately 10 cm (3.9 in) from the HPL connector

Engine Controls Component Views

--

AF D2 (DIODE)

AF Harness, approximately 10 cm (3.9 in) from the LPL connector

Engine Controls Component Views

--