P18B6 2017 GMC Sierra Code - Internal Mode Switch 'B' Circuit Shorted
Quick Answer
The P18B6 diagnostic trouble code (DTC) for a 2017 GMC Sierra indicates an issue with the Internal Mode Switch 'B' Circuit being shorted. Common causes include Wiring harness damage or corrosion, Faulty Internal Mode Switch, Malfunctioning control module. 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
- P18B6 2017 GMC Sierra indicates Internal Mode Switch 'B' Circuit Shorted.
- Common causes
- Common causes include Wiring harness damage or corrosion, Faulty Internal Mode Switch, Malfunctioning control module.
- 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.
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Code P18B6 2017 GMC Sierra Description
The P18B6 diagnostic trouble code (DTC) for a 2017 GMC Sierra indicates an issue with the Internal Mode Switch 'B' Circuit being shorted. The Internal Mode Switch (IMS) is a component within the transmission that communicates with the vehicle's control module to determine the desired gear selection. In this case, the 'B' circuit refers to a specific circuit within the IMS that has been identified as having a short.
Common Causes of P18B6 2017 GMC Sierra
- Wiring harness damage or corrosion
- Faulty Internal Mode Switch
- Malfunctioning control module
- Electrical short circuit
- Poor connection within the circuit
Symptoms of P18B6 2017 GMC Sierra
- Erratic shifting behavior
- Incorrect gear selection
- Transmission slipping
- Illumination of the Check Engine Light
- Reduced fuel efficiency
How to Fix P18B6 2017 GMC Sierra
- Begin by conducting a thorough inspection of the wiring harness and connectors associated with the Internal Mode Switch 'B' circuit.
- Test the Internal Mode Switch for proper operation and replace if necessary.
- Check the control module for any faults or errors and address as needed.
- Repair any damaged wiring or connectors in the circuit.
- Clear the DTC and perform a test drive to ensure the issue has been resolved.
Cost to Fix P18B6 2017 GMC Sierra
The typical repair costs for addressing a P18B6 code on a 2017 GMC Sierra can vary depending on the specific cause of the issue. Parts such as a new Internal Mode Switch or wiring harness may range from $100 to $300, while labor costs can add an additional $100 to $300. Overall, the total repair cost could fall within the range of $200 to $600. It's important to note that diagnosis time and labor rates at auto repair shops can vary, so it's advisable to check with local shops for a more accurate estimate.
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Frequently Asked Questions about P18B6 2017 GMC Sierra Code
1. What does the OBDII code P18B6 mean on a 2017 GMC Sierra?
P18B6 indicates that the Internal Mode Switch 'B' circuit has a short, which typically refers to an electrical issue in the transmission range selector circuit.
2. What are the symptoms of code P18B6 in a 2017 GMC Sierra?
Common symptoms include the vehicle stuck in a specific gear, the inability to shift gears, illumination of the check engine light, or erratic shifting behavior.
3. What causes the P18B6 code to appear on a 2017 GMC Sierra?
The most common causes are damaged wiring, a short circuit in the Internal Mode Switch 'B' circuit, a faulty transmission range sensor, or a malfunctioning transmission control module (TCM).
4. Can I still drive my 2017 GMC Sierra with the P18B6 code?
While it may still be drivable, driving with this code can lead to further transmission issues or leave the vehicle stuck in an unsafe gear. It’s best to address the issue promptly.
5. How do I diagnose the P18B6 code on a GMC Sierra?
Start by checking the wiring and connectors for damage or corrosion. Use a multimeter to test the Internal Mode Switch 'B' circuit for shorts. If the wiring is intact, inspect the transmission range sensor and TCM.
6. How much does it cost to fix the P18B6 code on a 2017 GMC Sierra?
Repair costs can vary depending on the issue. Replacing a damaged wire or connector may cost $100-$200, while replacing the transmission range sensor or TCM can cost $300-$1,000 or more.
7. Can a bad battery cause the P18B6 code on a GMC Sierra?
A weak or failing battery is unlikely to directly cause the P18B6 code, but electrical issues related to low voltage could potentially exacerbate circuit problems.
8. What tools are needed to troubleshoot the P18B6 code?
You will need an OBDII scanner, a multimeter, and possibly a wiring diagram for the transmission system to accurately diagnose the issue.
9. Does the P18B6 code always mean the transmission range sensor is faulty?
No, while a faulty transmission range sensor is a common cause, the issue could also be due to damaged wiring, a short circuit, or a problem with the TCM.
10. Will clearing the P18B6 code fix the problem on my 2017 GMC Sierra?
Clearing the code may turn off the check engine light temporarily, but the underlying issue must be repaired to prevent the code from returning.
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