P0632 Odometer Not Programmed – ECM/PCM
OBD-II Trouble Code Technical Description
Odometer Not Programmed – ECM/PCM
What does that mean?
This is a generic diagnostic trouble code (DTC) and applies to many OBD-II vehicles (1996-newer). That may include but is not limited to vehicles from Mercedes Benz, Ford, Dodge, Ram, Jeep, Hyundai, etc. Although generic, the exact repair steps may vary depending on year, make, model and powertrain configuration.
When a code P0632 is stored, it means that the engine control module (ECM) or powertrain control module (PCM) has detected an incorrect or non-existent odometer (mileage) reading.
Since the inception of OBD-II diagnostic systems, a method of recording vehicle mileage has been programmed into each ECM/PCM. Other controllers (including the instrument panel control - IPC - module) may also be programmed to record mileage but a federal mandate demands that the ECM/PCM is programmed as such.
The primary reason for government and auto industry insistence that the ECM/PCM be programmed to record mileage is to prevent odometer tampering. System controllers cannot be swapped between vehicles without being programmed with the correct vehicle mileage. If controllers could be randomly swapped between vehicles, odometer readings would be far less accurate if not totally unreliable. When an ECM/PCM is replaced, it must be programmed with the vehicle’s odometer reading and VIN (among other things).
If the ECM/PCM fails to find or recognize an acceptable odometer reading, a code P0632 will be stored and a malfunction indicator lamp (MIL) may be illuminated. The ECM/PCM searches for the odometer reading and compares it with the IPC odometer figure each time the key is turned on and the self-test function is energized.
Photo of a PCM with the cover removed:
What is the severity of this DTC?
A stored code P0632 should be categorized as severe, particularly if you are not familiar with the history of the vehicle in question. Odometer inconsistencies may result in serious vehicle registration problems.
What are some of the symptoms of the code?
Symptoms of a P0632 trouble code may include:
No (or intermittent) odometer display Incorrect odometer display Erratic speedometer operation Vehicle security system may be activated Other diagnostic codes will likely be storedWhat are some of the common causes of the code?
Causes for this code may include:
ECM/PCM programming error ECM/PCM swapped between vehicles and/or replaced without being properly programmed ECM/PCM failure IPC programming error Instrument panel cluster replacement without proper reprogrammingWhat are some P0632 troubleshooting steps?
Unlike most other stored codes, the P0632 is usually related to controller failure or some type of a controller programming error. Due to the delicate nature of certain parameters which must be programmed into the related controllers (VIN and mileage), access to reprogramming equipment must be limited to qualified personnel. Without the means to reprogram the controller in question, making a successful repair will be very difficult (if not impossible).
You will need a diagnostic scanner and a reliable source of vehicle information to arrive at a reasonable diagnosis of a code P0632. Use the vehicle information source to search for applicable technical service bulletins (TSB). If you locate a TSB that matches the vehicle make and model, symptoms exhibited, and the code stored, it will help to point you in the right direction.
I would connect the diagnostic scanner to the vehicle diagnostic port and read the odometer as it is perceived by the ECM/PCM and the IPC. Compare the mileage on the diagnostic scanner to the odometer reading in the IPC and on the instrument panel cluster. If these figures are not consistent, suspect that a mil
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