C1298 in EBTCM and U1040 in PCM , During Key Power Mode Changes - kw ABS calibration electrical intermittent module

The following diagnosis might be helpful if the vehicle exhibits the described symptoms in the PI.

An intermittent C1298 stored in the EBTCM and a U1040 stored in the pcm. The codes will only set during key up when the key is turned from "Off" to "Start" and back to "Run". The codes will set during or shortly after the normal key power mode changes referenced above. The codes can be cleared during the same drive cycle in which they set and will not reset during that same drive cycle. If the key is turned back to off and the process above is repeated the codes will reset.

1. Checks for proper voltage at ignition 1 pin 63 and ignition 0 pin 19 may find that the voltage levels are correct for the key position that they are checked in. (If not correct these issues prior to proceeding)
2. If ignition power is jumpered temporarily from the PCM ignition fuse to the ignition 0 fuse the condition will not occur.

Cause: Programming error in the pcm.

Replace the PCM and reprogram it.

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Please follow this diagnosis process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed. If these steps do not resolve the condition, please contact GM TAC for further diagnostic assistance.

(2000-02 Cadillac Eldorado) and (2000-05 Cadillac Deville)

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