What Does P0886 Mean?
The TCM has detected a low voltage condition on the TCM power relay control circuit. This means the control signal voltage used to energize the power relay is below the expected threshold, which may result in the relay not engaging reliably or not engaging at all. The TCM may experience intermittent power loss as a result.
Common Causes
30%
High resistance in relay control circuit wiring
25%
Corroded relay socket causing voltage drop
20%
Weak TCM relay driver output
15%
Short to ground in relay control circuit
10%
Failing relay with excessive coil resistance
Diagnostic Steps
1
Measure voltage at the relay control circuit with relay energized — compare to expected battery voltage or TCM command voltage.
2
Perform a voltage drop test across the relay control circuit from TCM output pin to the relay coil pin — should be minimal.
3
Inspect the relay socket for corrosion, burned contacts, or loose terminals that could cause high resistance.
4
Check the relay control wiring for damage, exposed copper, or areas where insulation may have melted near heat sources.
5
Test the relay coil resistance — compare to manufacturer specification; higher resistance means the relay is degrading.
Estimated Repair Cost
$30 - $600
Parts + labor, varies by vehicle and location
The TCM has detected a low voltage condition on the TCM power relay control circuit. This means the control signal voltage used to energize the power relay is below the expected threshold, which may result in the relay not engaging reliably or not engaging at all. The TCM may experience intermittent...
The most common cause of P0886 (TCM Power Relay Control Circuit Low) is: High resistance in relay control circuit wiring
Typical repair costs for P0886 range from $30 to $600, depending on the vehicle, location, and whether you do it yourself or go to a shop.
TCM may have inconsistent power leading to intermittent shifting problems. Drive at moderate speeds and avoid situations requiring rapid acceleration or towing.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0886 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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