Vehicle Overspeed Condition
The vehicle has been operated in a manner which has allowed the vehicle speed to exceed the calibration limit (usually 100 mph).
Code Set Parameters
If the vehicle speed sensor or wheel speed sensors provide the PCM or other controllers with a signal that exceeds the maximum calibration limit, a code will be stored and a service engine soon lamp may be illuminated. Some models require multiple failure cycles in order for the service engine soon lamp to be illuminated.
There are typically no symptoms associated with the conditions required to store this code.
This code is normally caused by driver error. Most vehicles are equipped with an electronic speed limiting system that disables engine operation when a certain vehicle speed is reached. Technicians report that drivers purposefully accelerate to the predetermined limit and allow the vehicle to coast (primarily downhill) in order to exceed calibration limits. They are often surprised when a code is stored and a service engine soon lamp is illuminated.
One Common misdiagnosis results in unnecessary vehicle speed sensor replacement.
- Most late model vehicles utilize a computerized fuel disabling system that is activated when the vehicle speed reaches a predetermined limit
- This feature is used for safety reasons and to meet federal mandates.
Because this condition is often created by driver error, there is very little to consider in the way of a diagnostic strategy.
A scanner (or code reader) and a digital volt/ohmmeter will be helpful in successfully diagnosing this code-storing condition.
Begin your diagnosis with a visual inspection of all wiring and connectors
- Repair or replace damaged, disconnected, shorted, or corroded wiring, connectors, and components as necessary
- Always retest the system after repairs are completed to ensure success.
If all system wiring, connectors, and components (Including fuses) appear to be in normal working order, connect the scanner (or code reader) to the diagnostic connector and record all stored codes and freeze frame data
- This information can be extremely helpful in diagnosing intermittent conditions that may have contributed to this code being stored
- After the codes are cleared, operate the vehicle to see if the code returns
- If the code fails to immediately return, you may have an intermittent condition
- Intermittent conditions can prove to be quite a challenge to diagnose and in extreme cases may have to be allowed to worsen before a correct diagnosis can be made.
Clear the codes and test drive the vehicle to ensure that the code doesn’t return
- If the code does not reset, driver error is the most likely cause.
If the code does return, observe the vehicle speed sensor (using the scanner) signal
- If the speed sensor data appears erratic or fails to change with conditions, replace the sensor and retest the system.
Should the sensor appear normal, visually inspect all vehicle speed sensor circuitry and electrical connectors
- Repair or replace wiring, connectors, or components that are damaged, corroded, or disconnected and retest the system
If the problem persists, disconnect the electrical connector from the PCM and perform a resistance and continuity test on vehicle speed and wheel speed system circuits between the sensor/s and the control modules
- Repair or replace shorted or open circuits as required.
If all system circuits and sensor appear to be operating normally, suspect a faulty PCM or other system controller