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Contents

Section: Ccc Tbi Tests W/codes

MODEL IDENTIFICATION

BASIC DIAGNOSTIC PROCEDURES

CLEARING TROUBLE CODES

Without "SCAN" Tester

With "SCAN" Tester

TROUBLE CODE DETERMINATION (HARD OR INTERMITTENT)

Diagnostic Charts

System Check

Field Service Mode Check

DIAGNOSTIC TOOLS

Circuit Description

Test Description

Diagnostic Aids

Fuel Module Check Procedure

System Too Lean (High Air/Fuel Ratio)

System Too Rich (Low Air/Fuel Ratio)

Throttle Body

A/C Compressor Relay Failure

O2 Sensor Wire

Fuel Contamination

Fuel Pressure

AIR System

Circuit No. 413

Sensor Harness

HEI Shielding

Canister Purge

MAP Sensor

Pressure Regulator

TPS

CODE 51 - FAULTY MEM-CAL (2.5L)

CODE 51 - PROM PROBLEM (2.8L/4.3L/5.0L/5.7L/7.4L)

CODE 52 - FUEL CALPAK MISSING (2.8L/4.3L/5.0L/5.7L/7.4L)

CODE 53 - SYSTEM OVER VOLTAGE (2.5L)

CODE 55 - ECM PROBLEM (2.8L/4.3L/5.0L/7.4L)

Circuit Test Description

A/C Compressor Or Relay Failure

All sections

Test Description GMC Magnavan G3500

Ccc Tbi Tests W/codes

Test Description

Note. Test numbers refer to test numbers on diagnostic chart.

If fuse in holder is blown, see wiring diagram for Code 54 for complete electrical circuit.
Using a test light connected to 12 volts, probe each system ground circuit to ensure good ground is present. See ECM voltage pin charts for ECM pin locations of ground circuits.