Transmission Control System MIL Request Circuit Low
What it means
P0898 means the circuit the transmission controller uses to request the dashboard warning light is reading abnormally low — usually a short to ground or a wiring fault. This is the signal path the TCM uses to make the check-engine light come on when it detects a transmission problem, so the fault is about the warning system itself rather than how the transmission drives. The engine and transmission operate normally; the concern is that the warning lamp may not work as intended.
Can I keep driving? Safe to drive; this is a wiring or communication fault in the warning-light request line, not a mechanical transmission problem.
Common symptoms
What you'll notice
- Check-engine light behaves abnormally (may not light when expected)
- Difficulty retrieving codes via the warning lamp
- Communication trouble with the TCM
- Other transmission-related codes may be present
Common causes
Most likely first
- Short-to-ground or low-voltage fault in the MIL request circuit wiringLikely
- Blown fuse or poor groundCommon
- Faulty transmission control moduleCommon
- Corroded or loose connectorLess often
How to diagnose & fix
Work through it in order
- Inspect the MIL request circuit wiring for shorts to ground or damage.
- Check related fuses and ground connections.
- Repair the wiring or clean the grounds as needed.
- Test or replace the TCM if the wiring checks out.
- Clear the code and retest.
FAQ
Quick answers
Is it safe to drive with P0898?+
Can I just clear P0898?+
Related codes
Often seen with P0898
Read & clear P0898 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.