Trouble Code Identification
NOTE:
Trouble codes retrieved from PCM/TCM may be either engine or transmission related. Engine-related codes are covered in this article. For transmission-related codes, see G - TESTS W/ CODES - ELECTRONIC TRANSMISSION article. Refer to TROUBLE CODE IDENTIFICATION to determine if code is engine or transmission related.
- The DEC system codes indicate failure of a specific sensor and/or circuit. Sensor/circuit diagnosis may indicate replacement of ECM. Code 51 indicates PROM is either improperly installed or has failed.
- Code 52 indicates ECM has failed and must be replaced. If condition is still not corrected after replacing ECM, the following may be the cause:
- An incorrect ECM or PROM application may cause a malfunction, which may or may not set a code.
- The ECM 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 ECM 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 ECM failure. Use Short Circuit Tester (J-34636) to check for short circuits.
TROUBLE CODE IDENTIFICATION
| Code | Probable Cause | ||
|---|---|---|---|
| 12 (1) | No Engine Speed Sensor Reference Pulse To PCM/TCM | ||
| 14 (1) | CTS Voltage Low (Sensor Or Signal Line Grounded) | ||
| 15 (1) | CTS Voltage High (Sensor, Connections, Or Wires Open) | ||
| 21 (1) | TPS Voltage High (Open Circuit Or Misadjusted TPS) | ||
| 22 (1) | TPS Voltage Low (Circuit Grounded) | ||
| 23 (1) | TPS Not Calibrated (.25-1.3 Volts At Curb Idle) | ||
| 24 (1) | Vehicle Speed Sensor Circuit Open Or Grounded | ||
| 28 | Pressure Switch Manifold Range Circuit Open Or Shorted | ||
| 31 (1) | MAP Voltage Low (Circuit Open Or Shorted To Ground) | ||
| 32 (1) | EGR Error (Improper Vacuum Signal) | ||
| 33 (1) | MAP Voltage High (Circuit Open Or Shorted To Ground) | ||
| 39 | TCC Stuck Off (Faulty TCC Solenoid) | ||
| 51 (1) | Improperly Installed/Faulty PROM | ||
| 52 (1) | ECM Fault | ||
| 53 (1) | Voltage Reference Overload | ||
| 58 | TTS High Temperature (Sensor Or Signal Line Grounded) | ||
| 59 | TTS Low Temperature (Sensor, Connections, Or Wires Open) | ||
| 68 | Overdrive Ratio Error (Engine RPM Greater Than Input Speed) | ||
| 73 | Force Motor Commanded Amperage Differs From Return | ||
| 75 | System Voltage Low (Charging System Problem) | ||
| 81 | QDM Solenoid "B" Monitored Voltage Differs From Commanded | ||
| 82 | QDM Solenoid "A" Monitored Voltage Differs From Commanded | ||
| 83 | QDM TCC Monitored Voltage Differs From Commanded | ||
| 85 | Undefined Gear Ratio (Input Or Output Sensor Failure) | ||
| 86 | Shift Solenoid "B" Stuck On (Commanded Gear Not Engaged) | ||
| 87 | Shift Solenoid "B" Stuck Off (Commanded Gear Not Engaged) | ||
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