What does GM fault code P0708 mean?

Q: What does GM fault code P0708 mean?

P0708 indicates: No-Crank / Range Shift Inhibited Fix: LOGIC: Transmission Range Sensor (Neutral Safety / PRNDL) High Input. ACTION: Inspect the dual-connector Neutral Safety Switch (NSBU switch) mounted externally on the driver's side of the transmission case. Check for backed-out terminal pins, water intrusion, or internal corrosion. Realign the switch using the neutral alignment line or replace.

GM Fault Code

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P0708

No-Crank / Range Shift Inhibited

System

Transmission Range

Symptom

No-Crank / Range Shift Inhibited

Diagnosis & fix steps

LOGIC: Transmission Range Sensor (Neutral Safety / PRNDL) High Input. ACTION: Inspect the dual-connector Neutral Safety Switch (NSBU switch) mounted externally on the driver's side of the transmission case. Check for backed-out terminal pins, water intrusion, or internal corrosion. Realign the switch using the neutral alignment line or replace.

Red Seal field insights

The NSBU Failure: Early external Allison 1000/2000 NSBU switches are vulnerable to road salt and wash water. Water penetrates the internal slider tracks, shorting the contact logic and throwing range inhibit faults.

Same code keeps coming back?

That's a program problem, not a part problem. Book a 30-minute uptime review with Grant, a Red Seal Heavy Duty Technician.

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Read before you touch anything

This is general reference information, not a repair manual. It is for trained, qualified technicians.
Fault codes, meanings and procedures vary by model, serial number and software version. Confirm the code and the procedure against the manufacturer's service manual before acting.
Follow the OEM service manual, torque specs and your site's safety procedures: lockout/tagout, block raised equipment, relieve hydraulic, fuel and air pressure, and let hot systems cool.
You use this information at your own risk. Adventure Mechanical and AM Fleet Integrity accept no liability for damage, injury, downtime or loss arising from its use.
Not affiliated with or endorsed by any manufacturer. Brand names are used only to identify the equipment a code applies to.

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