P0890
TCM Power Relay Sense Circuit Low
The TCM monitors the output side of its power relay; when the sense voltage is below threshold while relay is commanded closed, this code sets.
- Check engine light: Yes
- Emissions related: No
- Repair difficulty: medium
Symptoms
- Check engine or transmission warning light on
- Harsh, delayed, or missing shifts
- Possible limp mode (locked in one gear)
- Slipping or shuddering during gear changes
Common causes
Ordered by how often each turns out to be the cause.
- Relay failed openCommon
- Open wiring at sense inputPossible
- Connector pins corroded - high contact resistanceLess likely
Parts involved
- TCM Relay
- Wiring Harness
- TCM
P0890 is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.