GM Service Manual Online
For 1990-2009 cars only

DTC

Description

Type

Illuminate MIL

When a type A diagnostic fails, a DTC sets immediately and the Malfunction Indicator Lamp (MIL) illuminates. When a type B diagnostic fails, a DTC sets and the MIL illuminates if the fault is present after two consecutive drive trips. A type C DTC is not used during CNG operation. A type D DTC sets after two failures and stores in memory but does not illuminate the MIL.

12

Diagnostic System Ready

N/A

N/A

13

Function Readiness

N/A

N/A

14

ECT Sensor Circuit High Voltage

B

Yes

15

ECT Sensor Circuit Low Voltage

B

Yes

16

ECT Excessive Time to Closed Loop

A

Yes

21

TP Sensor Circuit High

B

Yes

22

TP Sensor Circuit Low

B

Yes

23

IAT Sensor Circuit Low Voltage

B

Yes

25

IAT Sensor Circuit High Voltage

B

Yes

26

TP Sensor Performance

B

Yes

27

Quad Driver Output

D

No

31

EGR Valve Circuit

B

Yes

32

MAP Sensor Performance

B

Yes

33

MAP Sensor Circuit High

B

Yes

34

MAP Sensor Circuit Low

B

Yes

41

CKP Sensor Circuit

A

Yes

42

O2S Insufficient Activity Sensor 1

B

Yes

44

O2S Circuit Low Voltage Sensor 1

B

Yes

45

O2S Circuit High Voltage Sensor 1

B

Yes

51

Gas Mass Sensor Circuit Low Frequency

A

Yes

52

Gas Mass Sensor Circuit High Frequency

A

Yes

53

Gas Mass Sensor Circuit Range Performance

A

Yes

55

Fuel Trim System Lean

B

Yes

56

Fuel Trim System Rich

B

Yes

58

AF ECU Failure

A

Yes

66

Fuel Pressure Sensor Circuit Low Voltage

A

Yes

67

Fuel Pressure Sensor Circuit High Voltage

D

No