What Does P0297 Mean?
The ECM has detected that the vehicle has exceeded its programmed maximum speed limit. This is an informational/protective code set when the vehicle's speed surpasses the electronic speed governor threshold. It may indicate a malfunctioning vehicle speed sensor providing erroneous readings, a transmission issue causing incorrect gear ratios, or the vehicle was actually driven above the speed limiter. The driver may notice the engine cutting power or fuel being restricted.
Common Causes
35%
Vehicle was actually driven above the programmed speed limiter threshold
25%
Faulty vehicle speed sensor (VSS) sending erroneous high-speed signals to the ECM
20%
Incorrect tire size or final drive ratio causing the ECM to calculate a higher speed than actual
12%
Transmission control module reporting incorrect gear ratio or output shaft speed
8%
ECM software calibration issue or aftermarket tune altering speed limiter parameters
Diagnostic Steps
1
Review freeze frame data for the stored vehicle speed value at the time the code was set; compare with known speed limiter threshold for the vehicle (typically 110-155 mph depending on make/model).
2
Monitor live vehicle speed PID while driving at a known speed (verified by GPS); compare scan tool reading to GPS speed to verify VSS accuracy.
3
Inspect the vehicle speed sensor wiring and connector for damage; check the reluctor ring or tone wheel for missing teeth, debris, or excessive runout.
4
Verify the correct tire size is installed; compare with the door jamb placard specification. Undersized tires will cause the ECM to over-report speed.
5
Check for aftermarket ECM tuning or performance modifications that may have altered speed limiter settings or introduced calibration errors.
Estimated Repair Cost
$0 - $400
Parts + labor, varies by vehicle and location
The ECM has detected that the vehicle has exceeded its programmed maximum speed limit. This is an informational/protective code set when the vehicle's speed surpasses the electronic speed governor threshold. It may indicate a malfunctioning vehicle speed sensor providing erroneous readings, a transm...
The most common cause of P0297 (Vehicle Overspeed Condition) is: Vehicle was actually driven above the programmed speed limiter threshold
Typical repair costs for P0297 range from $0 to $400, depending on the vehicle, location, and whether you do it yourself or go to a shop.
If the vehicle was actually overspeeding, reduce speed immediately as tires, brakes, and suspension may not be rated for extreme speeds. If the speed sensor is faulty, the speedometer may read incorrectly, affecting safe driving. Verify sensor accuracy before normal driving.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0297 to identify the root cause.
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Quick Info
Category
Powertrain
System
Powertrain Control System
Difficulty
Type
Generic (SAE)
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