The P0802: Transmission Control System MIL Request Circuit/Open code refers to an open or malfunctioning circuit in the transmission control system responsible for triggering the Malfunction Indicator Lamp (MIL). This issue can be caused by faulty wiring, connector issues, or a malfunctioning transmission control module (TCM).
P0802 – Quick Overview
| Code | Information |
|---|---|
| Meaning | P0802: Transmission Control System MIL Request Circuit/Open |
| Is it serious? | Yes, since the open circuit may prevent the MIL from illuminating when a critical transmission issue occurs, potentially hiding transmission problems. |
| Possible causes | – Open circuit in transmission control system MIL request – Faulty wiring or connectors – Faulty transmission control module (TCM) |
| How to diagnose? | – Inspect circuit for continuity – Check and repair wiring or connectors – Replace faulty TCM if needed |
P0802 Meaning
The P0802 code indicates that the transmission control system has detected an open circuit in the MIL request line, preventing the proper operation of the Malfunction Indicator Lamp. This lamp is essential for alerting the driver to transmission problems. A faulty TCM, damaged wiring, or poor connections may be the root cause.
Step-by-step diagnostic guide
| Action | Description | Tools Needed |
|---|---|---|
| Check for Other Codes | Use an OBD-II scanner to check for additional transmission-related codes that may give more insight into the problem. | OBD-II Scanner |
| Inspect Circuit for Continuity | Use a multimeter to test the MIL request circuit for continuity and ensure there are no breaks or opens in the circuit. Compare readings against manufacturer specifications. | Multimeter |
| Inspect Wiring and Connectors | Visually inspect the wiring and connectors leading to the TCM for signs of damage, wear, or corrosion that may be causing the open circuit. | Flashlight, Multimeter, Safety Gloves |
| Check Transmission Fluid | Ensure that the transmission fluid level is correct and free of contaminants, as low or dirty fluid can contribute to transmission-related issues. | Transmission Fluid Tester, Dipstick |
| Test Transmission Control Module (TCM) | If the wiring and connectors are functioning properly, test the TCM for faults or communication issues that may be causing the MIL request malfunction. | Diagnostic Scanner, TCM Testing Tools |
| Repair or Replace Faulty Components | If the MIL request circuit is open, repair the wiring or replace the faulty connectors. If the TCM is malfunctioning, replace it with a new one per manufacturer specifications. | Replacement Parts, Wrenches, Screwdrivers |
| Clear the Code and Test Drive | After repairing or replacing components, clear the code using an OBD-II scanner and test drive the vehicle to ensure the problem is resolved. | OBD-II Scanner |
| Recheck for Codes | After the test drive, rescan the vehicle to ensure the P0802 code has not returned. | OBD-II Scanner |
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I test OBD-II scanners and make DIY Engine diagnostics guides to help you solve your car problems without having to depend on the mechanic. A lot of them will try to scam you or are just no help at all. About Juraj Lukacko