What Does P0889 Mean?
The TCM has detected a range or performance issue with the TCM power relay sense circuit. The sense voltage is present but is not within the expected range, or it is not responding correctly to relay state changes. This means the relay may be partially engaging, or the sense circuit has high resistance that distorts the voltage reading.
Common Causes
30%
Worn relay contacts causing voltage drop on sense circuit
25%
High resistance in sense circuit wiring or connectors
20%
Corroded relay socket affecting both power delivery and sense feedback
15%
Weak battery causing relay sense voltage to be outside expected range
10%
TCM internal sense circuit calibration drift
Diagnostic Steps
1
Measure voltage at the relay sense output with relay energized and compare to battery voltage — a significant drop indicates relay contact wear.
2
Perform a voltage drop test across the relay contacts (input to output) while loaded — should be less than 0.1V.
3
Inspect the relay socket for signs of heat damage, arcing, or corrosion on the contact pins.
4
Check the sense wire from relay output to TCM for high resistance — total circuit resistance should be minimal.
5
Replace the relay if contact resistance is elevated; if the problem persists, inspect the TCM sense input for damage.
Estimated Repair Cost
$30 - $500
Parts + labor, varies by vehicle and location
The TCM has detected a range or performance issue with the TCM power relay sense circuit. The sense voltage is present but is not within the expected range, or it is not responding correctly to relay state changes. This means the relay may be partially engaging, or the sense circuit has high resista...
The most common cause of P0889 (TCM Power Relay Sense Circuit Range/Performance) is: Worn relay contacts causing voltage drop on sense circuit
Typical repair costs for P0889 range from $30 to $500, depending on the vehicle, location, and whether you do it yourself or go to a shop.
The TCM may misinterpret its power status and enter precautionary failsafe modes. Shifting quality may be degraded. Schedule a repair to restore reliable TCM operation.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0889 to identify the root cause.
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Quick Info
Category
Powertrain
System
Transmission Control Module Power Supply
Difficulty
Type
Generic (SAE)
Recommended Tools
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