What Does P0951 Mean?
DTC P0951 indicates the Auto Shift Manual control circuit is operating outside its expected performance range. The TCM detects that the shift actuator or control mechanism is responding but not within the correct parameters, such as slow actuation, incomplete travel, or excessive effort required. This suggests component wear, mechanical binding, or partial electrical degradation rather than a complete circuit failure.
Common Causes
25%
Shift actuator motor worn or weakened (reduced torque output)
25%
Mechanical binding in the shift linkage or synchronizer mechanism
20%
Contaminated or degraded transmission fluid increasing shift effort
15%
High-resistance wiring connection reducing actuator power delivery
15%
Shift position sensor calibration drift causing performance mismatch
Diagnostic Steps
1
Step 1: Using a scan tool, monitor shift actuator position and timing data during commanded shifts. Compare actual shift completion times to manufacturer specifications.
2
Step 2: Check transmission fluid level and condition. Degraded, contaminated, or incorrect fluid specification can significantly increase shift effort and slow actuator response.
3
Step 3: Command individual gear selections via the scan tool and observe actuator current draw. Elevated current suggests mechanical binding; low current suggests a weak actuator.
4
Step 4: Inspect the shift linkage and mechanism for wear, damage, or debris that could impede smooth operation. Check for worn synchronizer rings or detent springs.
5
Step 5: Measure voltage drop across the actuator circuit connections during operation. Repair any high-resistance connections found in the power and ground circuits.
Estimated Repair Cost
$300 - $1,500
Parts + labor, varies by vehicle and location
DTC P0951 indicates the Auto Shift Manual control circuit is operating outside its expected performance range. The TCM detects that the shift actuator or control mechanism is responding but not within the correct parameters, such as slow actuation, incomplete travel, or excessive effort required. Th...
The most common cause of P0951 (Auto Shift Manual Control Circuit Range/Performance) is: Shift actuator motor worn or weakened (reduced torque output)
Typical repair costs for P0951 range from $300 to $1,500, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Performance degradation in the ASM control circuit results in slower or rougher shifts, which can be uncomfortable and potentially hazardous during maneuvers requiring quick gear changes. If the condition worsens, complete shift failure may occur.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0951 to identify the root cause.
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Quick Info
Category
Powertrain
System
Transmission / Auto Shift Manual Control
Difficulty
Type
Generic (SAE)
Recommended Tools
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