P1838 2017 GMC Sierra Code - Internal Mode Switch 'A' Circuit High Voltage
Quick Answer
The P1838 diagnostic trouble code (DTC) for a 2017 GMC Sierra indicates an issue with the Internal Mode Switch 'A' Circuit High Voltage. Common causes include Faulty Internal Mode Switch sensor, Damaged wiring or connectors in the IMS 'A' circuit, Malfunctioning transmission 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
- P1838 2017 GMC Sierra indicates Internal Mode Switch 'A' Circuit High Voltage.
- Common causes
- Common causes include Faulty Internal Mode Switch sensor, Damaged wiring or connectors in the IMS 'A' circuit, Malfunctioning transmission 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 P1838 2017 GMC Sierra Description
The P1838 diagnostic trouble code (DTC) for a 2017 GMC Sierra indicates an issue with the Internal Mode Switch 'A' Circuit High Voltage. The Internal Mode Switch (IMS) is a component of the transmission control system that helps the vehicle's computer determine the current gear selection. In this case, the 'A' circuit is reporting a high voltage, which can lead to incorrect gear selection, transmission shifting issues, and potential safety concerns.
Common Causes of P1838 2017 GMC Sierra
- Faulty Internal Mode Switch sensor
- Damaged wiring or connectors in the IMS 'A' circuit
- Malfunctioning transmission control module
- Corrosion or moisture in the circuit
- Electrical issues in the transmission system
Symptoms of P1838 2017 GMC Sierra
- Erratic shifting behavior
- Transmission slipping or sticking in a gear
- Reduced fuel efficiency
- Poor acceleration
- Illumination of the Check Engine Light
How to Fix P1838 2017 GMC Sierra
- Begin by performing a thorough inspection of the IMS sensor, wiring, and connectors to identify any visible damage or corrosion.
- Use a multimeter to test the voltage output of the IMS 'A' circuit to determine if it is indeed reporting high voltage.
- If the IMS sensor is faulty, replace it with a new, OEM-quality sensor to ensure proper operation.
- Repair any damaged wiring or connectors in the circuit and ensure proper connections are made.
- Clear the DTC from the vehicle's computer using a diagnostic scanner and test drive the vehicle to confirm that the issue has been resolved.
Cost to Fix P1838 2017 GMC Sierra
The typical repair costs for addressing the P1838 code on a 2017 GMC Sierra can vary depending on the exact cause of the issue. In general, replacing the IMS sensor and repairing any wiring or connectors may cost between $200 and $500, including parts and labor. However, it is essential to note that specific diagnosis time and labor rates at auto repair shops can vary based on factors such as location, vehicle make and model, and engine type. It is advisable to check with local auto repair shops for a more accurate estimate based on the specific circumstances.
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Frequently Asked Questions about P1838 2017 GMC Sierra Code
1. What does the OBDII code P1838 mean on a 2017 GMC Sierra?
P1838 indicates a high voltage issue in the Internal Mode Switch (IMS) 'A' circuit, which is part of the transmission range sensor system.
2. What are the common symptoms of code P1838 in a 2017 GMC Sierra?
Symptoms may include erratic shifting, the transmission stuck in one gear, a check engine light, or reduced performance.
3. What causes code P1838 to appear in a 2017 GMC Sierra?
Common causes include a faulty Internal Mode Switch, damaged wiring or connectors in the IMS circuit, or issues with the transmission control module (TCM).
4. Can driving with the P1838 code damage my 2017 GMC Sierra?
Yes, driving with this issue can cause further transmission damage or unsafe driving conditions due to improper shifting.
5. How is code P1838 diagnosed in a 2017 GMC Sierra?
A technician will use a scan tool to read live data, inspect the IMS circuit for wiring damage or loose connections, and test the switch for proper operation.
6. How can I fix the P1838 code on my 2017 GMC Sierra?
Repairs may include replacing the Internal Mode Switch, repairing or replacing damaged wiring, or reprogramming/updating the transmission control module.
7. What tools are needed to fix the P1838 code on my 2017 GMC Sierra?
Basic tools like a multimeter for testing voltage, a scan tool for diagnostics, and possibly specialized tools for accessing and replacing the IMS.
8. How much does it cost to repair code P1838 on a 2017 GMC Sierra?
The cost can vary, but replacing the Internal Mode Switch typically ranges from $150 to $400, depending on parts and labor.
9. Can a failing battery cause the P1838 code on a 2017 GMC Sierra?
While unlikely, a weak or failing battery can cause voltage irregularities that might trigger transmission-related codes, including P1838.
10. Is the P1838 code specific to GMC vehicles?
No, while the code can appear on other vehicles, it is manufacturer-specific and tailored to GM's Internal Mode Switch circuit issues.
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