Auxiliary PWM Driver 1 – Voltage Below Normal or Shorted to Low Source
|Fault Code: 2558
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 Pulse Width Modulated (PWM) Driver 1 Circuit
The transmission shift modulator uses this signal from the electronic control module (ECM) to determine when to shift the transmission. The return circuit is dependent on original equipment manufacturer (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.
Refer to the OEM diagram for the location of the transmission shift modulator.
Verify the electronic control module (ECM) calibration is correct. Check the calibration revision history found on QuickServe® Online for applicable fixes to the calibration stored in the ECM. If necessary, recalibrate the ECM. Refer to Procedure 019-032 (ECM Calibration Code) in Section 19 in the corresponding Troubleshooting and Repair Manual for the engine being serviced.
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.