Trouble Code Identification

NOTE: Trouble codes retrieved from PCM may be either engine or transmission related. Trouble codes retrieved from TCM are only transmission related. Both engine and transmission related codes are covered in this article. See the DTC IDENTIFICATION to determine if code is engine or transmission related.

The DEC/electronically-controlled transmission systems codes indicate failure of a specific sensor and/or circuit. Sensor/circuit diagnosis may indicate replacement of PCM/TCM. DTC 51 indicates PROM is either improperly installed or has failed.
If PCM/TCM is replaced at any point during diagnostic testing and if condition is still not corrected after replacing PCM/TCM, the following may be the cause:
- An incorrect PCM/TCM or PROM application may cause a malfunction, which may or may not set a code.
- The PCM/TCM connector may be the problem. Connector terminals may have to be removed from connector to be checked properly.
- PROM failure. Although the PROM rarely fails, it could be the cause of the problem.
- Replacement PCM/TCM may be faulty.
- Intermittent problem. Make a careful physical inspection of affected sensor/circuit.
- A shorted solenoid, coil relay, or harness may be the cause of PCM/TCM failure. Use Short Circuit Tester (J-34636) to check for short circuits.

DTC IDENTIFICATION

Code

Probable Cause

DTC 13 ⁽¹⁾

Engine Shutoff Solenoid Circuit Fault

DTC 14 ⁽¹⁾

ECT Sensor Circuit Low (High Temperature Indicated)

DTC 15 ⁽¹⁾

ECT Sensor Circuit High (Low Temperature Indicated)

DTC 16 ⁽¹⁾

Vehicle Speed Signal Buffer Fault

DTC 17 ⁽¹⁾

High Resolution Circuit Fault

DTC 18 ⁽¹⁾

Pump Cam Reference Pulse Error

DTC 19 ⁽¹⁾

Crankshaft Position Reference Error

DTC 21 ⁽¹⁾

APP No. 1 Circuit High (Models With PCM)

DTCS 21/22 ⁽²⁾

TP Sensor Circuit High/Low (4L80-E With TCM)

DTC 22 ⁽¹⁾

APP No. 1 Circuit Low (Models With PCM)

DTC 23 ⁽¹⁾

APP No. 1 Circuit Range Fault

DTC 24 ⁽²⁾

VSS Circuit Low (Transmission Output Speed Signal)

DTC 25 ⁽¹⁾

Accelerator Pedal Position (APP) No. 2 Circuit High

DTC 26 ⁽¹⁾

Accelerator Pedal Position (APP) No. 2 Circuit Low

DTC 27 ⁽¹⁾

APP No. 2 Circuit Range Fault

DTC 28 ⁽²⁾

Transmission Range Pressure Switch Circuit Fault

DTC 29 ⁽¹⁾

Glow Plug Relay Circuit Fault

DTC 31 ⁽¹⁾

EGR Control Pressure/BARO Sensor Ckt Low (High Vac)

DTC 32 ⁽¹⁾

EGR Circuit Error "G" Series

DTC 33 ⁽¹⁾

EGR Control Pressure/BARO Sensor Ckt High (Low Vac)

DTC 34 ⁽¹⁾

Injection Timing Stepper (ITS) Motor Circuit Fault

DTC 35 ⁽¹⁾

Injection Pulse Width Error (Response Time Short)

DTC 36 ⁽¹⁾

Injection Pulse Width Error (Response Time Long)

DTCS 37/38 ⁽²⁾

TCC Brake Switch Stuck On/Off

DTC 39 ⁽²⁾

TCC Stuck Off (4L80-E)

DTC 41 ⁽¹⁾

Brake Switch Circuit Fault

DTC 41 ⁽¹⁾

Brake Switch Circuit Fault - "P" Series

DTC 42 ⁽¹⁾

Fuel Temp Circuit Low (High Temp Indicated)

DTC 43 ⁽¹⁾

Fuel Temp Circuit High (Low Temp Indicated)

DTC 44 ⁽¹⁾

EGR Pulse Width Error - "G" Series

DTC 45 ⁽¹⁾

EGR Vent Error - "G" Series

DTC 46 ⁽¹⁾

Malfunction Indicator Light (MIL) Circuit Fault

DTC 47 ⁽¹⁾

IAT Sensor Circuit Low (High Temperature Indicated)

DTC 48 ⁽¹⁾

IAT Sensor Circuit High (Low Temperature Indicated)

DTC 49 ⁽¹⁾

SERVICE THROTTLE SOON Light Circuit Fault

DTC 51 ⁽¹⁾

PROM Problem (Faulty Or Incorrect PROM)

DTCS 52/53 ⁽²⁾

System Voltage High Long

DTC 54 ⁽¹⁾

PCM Fuel Circuit Error

DTC 56 ⁽¹⁾

Injection Pump Calibration Resistor Error

DTC 57 ⁽¹⁾

PCM 5-Volt Shorted

DTC 58 ⁽²⁾

Transmission Fluid Temp Sensor Circuit Low (High Temp Indicated) 4L60-E & 4L80-E

DTC 59 ⁽²⁾

Transmission Fluid Temp Sensor Circuit High (Low Temp Indicated) 4L60-E & 4L80-E

DTC 61 ⁽¹⁾

Turbo Boost Sensor Circuit High - "P" Series

DTC 62 ⁽¹⁾

Turbo Boost Sensor Circuit Low - "P" Series

DTC 63 ⁽¹⁾

Accelerator Pedal Position (APP) No. 3 Circuit High (Models With PCM)

DTCS 63/64 ⁽²⁾

BARO Sensor Circuit High/Low (4L80-E With TCM)

DTC 64 ⁽¹⁾

APP No. 3 Circuit Low (Models With PCM)

DTC 65 ⁽¹⁾

APP No. 3 Circuit Range Fault

DTC 66 ⁽²⁾

3-2 Control Solenoid Ckt Fault - "G" Series 4L60-E

DTC 67 ⁽²⁾

TCC Solenoid Circuit Fault - "G" Series 4L60-E

DTC 68 ⁽²⁾

Transmission Component Slipping (4L80-E)

DTC 69 ⁽²⁾

TCC Stuck On - "G" Series 4L60-E

DTC 69 ⁽¹⁾

TCC Stuck On (4L80-E)

DTC 71 ⁽¹⁾

Set/Coast Switch Fault (Models With PCM)

DTC 71 ⁽²⁾

Camshaft Position Sensor Circuit Low (4L80-E W/ TCM)

DTC 72 ⁽²⁾

Speed Sensor Circuit Loss (Trans Output Speed Signal)

DTC 73 ⁽²⁾

Pressure Control Solenoid Circuit (Current Error)

DTC 74 ⁽²⁾

Transmission Input Speed Sensor Circuit (4L80-E)

DTC 75 ⁽²⁾

System Voltage Low

DTC 76 ⁽¹⁾

Resume/Accel Switch Fault

DTC 78 ⁽¹⁾

Wastegate Solenoid Fault - "P" SERIES

DTC 79 ⁽²⁾

Transmission Fluid Overtemp - 4L60-E & 4L80-E

DTC 81 ⁽²⁾

2-3 Shift Solenoid Circuit Fault

DTC 82 ⁽²⁾

1-2 Shift Solenoid Circuit Fault

DTC 83 ⁽²⁾

TCC PWM Solenoid Circuit Fault

DTC 84 ⁽¹⁾

Accelerator Pedal Position (APP) Circuit Fault

DTC 85 ⁽²⁾

Undefined Ratio Error (4L80-E)

DTC 86 ⁽²⁾

Low Ratio Error (4L80-E)

DTC 87 ⁽²⁾

High Ratio Error (4L80-E)

DTC 88 ⁽¹⁾

TDC Offset Error

DTC 91 ⁽¹⁾

Cylinder Balance Fault No. 1 Cylinder

DTC 92 ⁽¹⁾

Cylinder Balance Fault No. 2 Cylinder

DTC 93 ⁽¹⁾

Cylinder Balance Fault No. 3 Cylinder

DTC 94 ⁽¹⁾

Cylinder Balance Fault No. 4 Cylinder

DTC 95 ⁽¹⁾

Cylinder Balance Fault No. 5 Cylinder

DTC 96 ⁽¹⁾

Cylinder Balance Fault No. 6 Cylinder

DTC 97 ⁽¹⁾

Cylinder Balance Fault No. 7 Cylinder

DTC 98 ⁽¹⁾

Cylinder Balance Fault No. 8 Cylinder

DTC 99 ⁽¹⁾

APP No. 2 (5-Volt Reference Fault)

⁽¹⁾	Code is engine related.

⁽²⁾	Code is transmission related.