Code 29

ECM SELF TEST - DTC 29

The ECM runs an internal self-test routine each time the ignition is switched ON.

The engine management program and data are stored within the ECM as a continuous list of numbers. When the ECM checks itself, it adds all the numbers together and compares the result to a programmed value (Checksum). If they are not the same, then some corruption of the data or program has taken place.

The ECM will flag DTC 29 if the self-test result does not equal the checksum.

Conditions Required For DTC 29 Flagging
Ignition - Ignition ON.
ECM self test - Checksum fail.

Limp Home Default
None

Possible Faults
- Low battery voltage.
- Poor connection to ECM power supplies.
- Poor ECM ground connections.
- ECM.

Diagnostic Notes
Check the battery condition (load test). If necessary. recharge or replace the battery. Clear the code and check for a reoccurrence. If DTC 29 does not reflag, the code may have been flagged during a previous period of low battery voltage. Do not replace an ECM if DTC does not reflag.

Flow Chart: DTC 29

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Flow Chart: DTC 29: