CM850 Electronic Control System – FAULT CODE 2558

Auxiliary PWM Driver #1 – Voltage Below Normal or Shorted to Low Source


Overview

CODE REASON EFFECT
Fault Code: 2558
PID: S057
SPN: 697
FMI: 4
LAMP: Amber
SRT: 

Auxiliary PWM Driver #1 – Voltage Below Normal or Shorted to Low Source. Low signal voltage detected at the analog torque circuit.

Can not control transmission.

Auxiliary PWM Driver #1 Circuit
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Circuit Description

The transmission shift modulator uses this signal from the ECM to determine when to shift the transmission. The return circuit is dependent on OEM wiring. It may be wired back to the ECM on some vehicles or wired to chassis or block ground on others. Consult the OEM wiring diagram for return circuit details.

Component Location

Refer to the OEM diagram for the location of the transmission shift modulator.

Shop Talk

This fault can be caused by the following:

  • A faulty transmission shift modulator
  • An short circuit to ground on the output device driver line
  • A short pin to pin in the output device driver line.

Refer to Troubleshooting Fault Code t05-2558

Last Modified:  08-Jul-2010