P0708 GMC Code - Transmission Range Switch Circuit High Voltage
Quick Answer
The Transmission Internal Mode Switch (IMS) consists of 5 internal switches, A, B, C, P, and Neutral Start. Common causes include Faulty Transmission Internal Mode Switch (IMS), Transmission Internal Mode Switch harness is open or shorted, Transmission Internal Mode Switch circuit poor electrical connection. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
- What it means
- P0708 GMC indicates Transmission Range Switch Circuit High Voltage.
- Common causes
- Common causes include Faulty Transmission Internal Mode Switch (IMS), Transmission Internal Mode Switch harness is open or shorted, Transmission Internal Mode Switch circuit poor electrical connection.
- Severity
- High - diagnose this code as soon as possible.
- Can I drive?
- Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
Code P0708 GMC Description
The Engine Control Module (ECM) supplies a signal circuit to the neutral start switch. The ECM uses the state of the neutral start switch state as confirmation that the transmission is in neutral or park before the engine starter is engaged.
The Diagnostic Trouble Code (DTC) will be set when the TCM detects the internal mode switch is reporting an illegal range for greater than 1 s.
What are the Possible Causes of the DTC P0708 GMC?
- Faulty Transmission Internal Mode Switch (IMS)
- Transmission Internal Mode Switch harness is open or shorted
- Transmission Internal Mode Switch circuit poor electrical connection
- Faulty Transmission Control Module (TCM)
How to Fix the DTC P0708 GMC?
Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.
Code Tech Notes
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What is the Cost to Diagnose the Code?
Labor: 1.0
To diagnose the P0708 GMC code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.
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Information for Specific GMC Models
- P0708 2014 GMC Sierra — Transmission Range Switch Circuit High Voltage
- P0708 2015 GMC Sierra — Transmission Range Switch Circuit High Voltage
- P0708 2016 GMC Sierra — Transmission Range Switch Circuit High Voltage
- P0708 2017 GMC Sierra — Transmission Range Switch Circuit High Voltage
- P0708 2018 GMC Sierra — Transmission Range Switch Circuit High Voltage
Frequently Asked Questions about P0708 GMC Code
1. What are common symptoms of OBDII code P0708 in a GMC related to the Transmission Range Switch Circuit High Voltage?
- Common symptoms include issues with shifting gears, inability to start the vehicle, and the transmission being stuck in a single gear.
2. What are the possible causes of OBDII code P0708 in a GMC?
- The code P0708 can be triggered by a faulty transmission range switch, damaged wiring or connectors in the circuit, or problems with the transmission control module.
3. How can I diagnose the OBDII code P0708 in my GMC?
- Diagnosing the code involves using a scan tool to read the code, checking the transmission range switch for proper operation, inspecting the wiring and connectors for damage, and testing the transmission control module.
4. Can I still drive my GMC with OBDII code P0708 present?
- It is not recommended to drive the vehicle with code P0708 as it can lead to further transmission issues and potential safety hazards. It's best to address the problem promptly.
5. How can I repair OBDII code P0708 in my GMC?
- Repairing the code may involve replacing the transmission range switch, repairing or replacing damaged wiring/connectors, or reprogramming the transmission control module.
6. Are there any DIY tips for fixing OBDII code P0708 in a GMC?
- While some simple checks like inspecting for loose connections or damaged wires can be done DIY, it is recommended to seek professional help for accurate diagnosis and repair of the issue.
7. How much does it typically cost to fix OBDII code P0708 in a GMC?
- The cost of fixing code P0708 can vary depending on the specific cause of the issue, but it may range from a couple of hundred dollars for simpler repairs to over a thousand dollars for more complex fixes.
8. Can a faulty transmission range switch cause OBDII code P0708 in a GMC?
- Yes, a faulty transmission range switch is a common cause of OBDII code P0708 in a GMC, as it can lead to high voltage readings in the circuit.
9. Will resetting the OBDII code P0708 in my GMC make it go away permanently?
- Resetting the code may temporarily clear the error, but if the underlying issue causing the code is not addressed, it is likely to reappear.
10. Is it necessary to get the transmission range switch from the dealership for OBDII code P0708 repair in a GMC?
- While getting the part from the dealership is an option, aftermarket or OEM equivalent parts may also be suitable for repairing OBDII code P0708 in a GMC.
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