The P0739: TCM Engine Speed Output Circuit High refers to a fault where the transmission control module (TCM) detects a high signal from the engine speed output circuit. This issue can stem from wiring problems, faulty components, or an electrical malfunction within the circuit.
P0739 – Quick Overview
| Code | Information |
|---|---|
| Meaning | P0739: TCM Engine Speed Output Circuit High |
| Is it serious? | Yes, this can cause communication errors between the engine and TCM, leading to improper transmission operation. |
| Possible causes | – High signal from TCM engine speed output circuit – Faulty circuit or components – Wiring issues |
| How to diagnose? | – Test the circuit for high signal – Inspect wiring and connectors – Replace faulty components if necessary |
P0739 Meaning
The P0739 code indicates that the transmission control module (TCM) is receiving a higher-than-expected signal from the engine speed output circuit. This may result from an issue with the circuit itself, faulty components, or damaged wiring. If left unresolved, it can lead to communication issues between the engine and the transmission, affecting performance.
Step-by-step diagnostic guide
| Action | Description | Tools Needed |
|---|---|---|
| Check for Other Codes | Use an OBD-II scanner to check for additional transmission-related or engine codes that could provide further insights. | OBD-II Scanner |
| Test the Circuit for High Signal | Use a multimeter or diagnostic tool to measure the signal from the TCM engine speed output circuit and verify if it is above specifications. | Multimeter, Diagnostic Scanner |
| Inspect Wiring and Connectors | Inspect the wiring and connectors between the engine speed sensors and the TCM for any signs of wear, corrosion, or damage. | Flashlight, Multimeter, Safety Gloves |
| Check for Electrical Faults | Test for any electrical faults such as short circuits, which may be causing the signal to be too high. | Circuit Tester, Multimeter |
| Replace Faulty Components | Replace any damaged wiring, connectors, or components in the circuit that are contributing to the high signal issue. | Replacement Parts, Wrenches, Screwdrivers |
| Clear the Code and Test Drive | After making repairs, clear the code using an OBD-II scanner and perform a test drive to ensure the problem is resolved. | OBD-II Scanner |
| Recheck for Codes | After the test drive, rescan the vehicle to ensure the P0739 code has not returned. | OBD-II Scanner |
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