P0802
Transmission Control System MIL Request Circuit/Open
Transmission — controls
Generic OBD-II
Medium
What it means
P0802 means there is an open or fault in the circuit the transmission control module uses to request the check-engine light (MIL). It is mainly a communication or wiring fault between the TCM and the instrument cluster or ECM, not a mechanical transmission failure. The engine still starts and runs; the priority is the circuit and any other transmission codes stored alongside it.
Medium
Can I keep driving? Usually yes — this is mostly a warning-light request circuit fault, but address any accompanying transmission codes.
Common symptoms
What you'll notice
- Check-engine light behaving abnormally (on, off, or not illuminating as expected)
- Stored transmission codes
- Difficulty shifting if related transmission faults are present
Common causes
Most likely first
- Open or damaged wiring in the MIL request circuitLikely
- Loose or corroded connectorCommon
- Failed transmission control module (TCM)Common
- Poor ground between modulesLess often
- Failed engine control module (ECM) — least commonLess often
How to diagnose & fix
Work through it in order
- Confirm the code and check for other transmission codes.
- Inspect the wiring and connectors in the MIL request circuit for opens or corrosion.
- Check grounds and continuity between the TCM and the ECM/instrument cluster.
- Repair any wiring faults; if the circuit is good, diagnose the TCM.
- Clear and re-test.
FAQ
Quick answers
Is it safe to drive with P0802?+
Usually yes — this is mostly a warning-light circuit fault. But address any accompanying transmission codes.
Can I just clear P0802?+
It returns until the open or fault in the MIL request circuit is repaired.
Related codes
Often seen with P0802
Read & clear P0802 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.
✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX