P18B8 2017 Chevrolet Silverado Code - Internal Mode Switch 'P' Circuit Shorted
Quick Answer
The internal mode switch indicates the Transmission Control Module (TCM) which gear position the vehicle operator has selected. Common causes include Faulty Transmission Internal Mode Switch, 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
- P18B8 2017 Chevrolet Silverado indicates Internal Mode Switch 'P' Circuit Shorted.
- Common causes
- Common causes include Faulty Transmission Internal Mode Switch, 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 P18B8 2017 Chevrolet Silverado Description
What are the Possible Causes of the DTC P18B8 2017 Chevrolet Silverado?
- Faulty Transmission Internal Mode Switch
- 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 P18B8 2017 Chevrolet Silverado?
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.
What is the Cost to Diagnose the Code?
Labor: 1.0
To diagnose the P18B8 2017 Chevrolet Silverado 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 P18B8 2017 Chevrolet Silverado Code
1. What does the OBDII code P18B8 mean on a 2017 Chevrolet Silverado?
P18B8 indicates a fault in the Internal Mode Switch (IMS), specifically a short circuit in the 'P' (Park) circuit of the transmission.
2. What are the common symptoms of code P18B8 in a 2017 Silverado?
Symptoms may include the inability to shift out of Park, a check engine light, erratic shifting, or the vehicle not recognizing the selected gear.
3. What causes the P18B8 code to be triggered?
Common causes include damaged wiring or connectors in the IMS circuit, a faulty Internal Mode Switch, or a short circuit in the transmission control system.
4. Can I drive my 2017 Silverado with the P18B8 code?
It’s not recommended to drive the vehicle, as the issue may prevent proper gear selection or shifting, potentially leading to unsafe driving conditions.
5. How do I diagnose the P18B8 code on my Silverado?
Diagnosis involves inspecting the IMS wiring and connectors for damage, testing the switch for continuity, and using a scan tool to monitor the transmission control module (TCM) data.
6. How do I fix the P18B8 code on a 2017 Chevrolet Silverado?
Repairs may include replacing damaged wiring or connectors, replacing the Internal Mode Switch, or reprogramming/repairing the TCM if necessary.
7. What tools are needed to troubleshoot the P18B8 code?
A multimeter for checking continuity, a scan tool capable of reading live transmission data, and basic hand tools for accessing the IMS and connectors.
8. How much does it cost to fix the P18B8 code on a Silverado?
Costs vary depending on the specific repair, but replacing the Internal Mode Switch typically costs between $200-$500, including parts and labor.
9. Can a low battery cause the P18B8 code in my Silverado?
While unlikely, electrical issues such as a weak battery or poor ground connection can occasionally contribute to communication errors or false codes.
10. Does the P18B8 code require reprogramming the TCM?
In some cases, reprogramming or updating the TCM software may be necessary after repairs to ensure proper operation of the transmission system.
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