P0708 2015 GMC Sierra 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 2015 GMC Sierra 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 2015 GMC Sierra 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 2015 GMC Sierra?
- 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 2015 GMC Sierra?
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
What is the Cost to Diagnose the Code?
Labor: 1.0
To diagnose the P0708 2015 GMC Sierra 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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Frequently Asked Questions about P0708 2015 GMC Sierra Code
1. What does the P0708 code mean on a 2015 GMC Sierra?
The P0708 code indicates a high voltage issue in the transmission range switch circuit, which monitors the gear position.
2. What are the symptoms of a P0708 code on a GMC Sierra?
Common symptoms include difficulty shifting gears, the transmission staying in limp mode, the check engine light turning on, and inaccurate gear readings on the dashboard.
3. What causes the P0708 code to appear?
Possible causes include a faulty transmission range sensor, damaged wiring or connectors in the circuit, or issues with the vehicle's PCM (Powertrain Control Module).
4. Can driving with a P0708 code damage my GMC Sierra?
Driving with this code can cause further transmission damage if left unresolved, as it may lead to improper shifting or transmission overheating.
5. How do you diagnose a P0708 code?
Diagnosis involves checking the transmission range sensor, inspecting the wiring and connectors for damage, and testing the voltage and continuity in the circuit.
6. How do you fix the P0708 code on a 2015 GMC Sierra?
Possible repairs include replacing the transmission range sensor, repairing or replacing damaged wiring or connectors, and updating or reprogramming the PCM if necessary.
7. Is a P0708 code expensive to fix?
The cost depends on the exact repair needed. Replacing a transmission range sensor typically costs between $150 and $300, while extensive wiring repairs or PCM replacement can be more expensive.
8. Can a bad battery cause a P0708 code?
A weak or failing battery is unlikely to directly cause this code but could contribute to electrical issues that affect the transmission range sensor circuit.
9. Will clearing the P0708 code reset the problem?
Clearing the code may temporarily turn off the check engine light, but the underlying issue must be fixed to prevent the code from returning.
10. How does the transmission range sensor affect the vehicle's performance?
The transmission range sensor communicates the gear position to the PCM. If it malfunctions, it can lead to incorrect shifting, reduced performance, and safety concerns.
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