What Does P1731 Mean?
During a PCM self-test or diagnostic routine, the engine speed did not decrease as expected when commanded. This indicates the throttle is not closing properly or something is preventing the engine from decelerating normally.
Common Causes
40%
Sticking throttle blade or throttle body carbon buildup
25%
Faulty electronic throttle actuator not returning to closed position
15%
Throttle position sensor misadjusted or failing
10%
Idle air control valve stuck open or malfunctioning
10%
PCM software calibration issue or corrupted memory
Diagnostic Steps
1
Step 1: Inspect throttle body for carbon deposits and sticky operation; clean thoroughly
2
Step 2: Monitor throttle position sensor values to confirm throttle returns to 0% at idle
3
Step 3: Manually operate throttle blade to check for binding or resistance
4
Step 4: Test electronic throttle actuator function using bidirectional scan tool controls
5
Step 5: Check for PCM updates or relearn procedures for electronic throttle system
Estimated Repair Cost
$100 - $500
Parts + labor, varies by vehicle and location
During a PCM self-test or diagnostic routine, the engine speed did not decrease as expected when commanded. This indicates the throttle is not closing properly or something is preventing the engine from decelerating normally.
The most common cause of P1731 (Insufficient Engine Speed Decrease During Self Test) is: Sticking throttle blade or throttle body carbon buildup
Typical repair costs for P1731 range from $100 to $500, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Potentially dangerous condition causing high idle or insufficient engine braking. Vehicle may be difficult to control and could continue accelerating when throttle released.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P1731 to identify the root cause.
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Quick Info
Category
Powertrain
System
Engine Management / Throttle Control
Difficulty
Type
Manufacturer
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