P18BB 2016 Chevrolet Silverado Code - Internal Mode Switch 'B' Circuit Stuck Off Invalid Voltage Range
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
- P18BB 2016 Chevrolet Silverado indicates Internal Mode Switch 'B' Circuit Stuck Off Invalid Voltage Range.
- 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 P18BB 2016 Chevrolet Silverado Description
What are the Possible Causes of the DTC P18BB 2016 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 P18BB 2016 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 P18BB 2016 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 P18BB 2016 Chevrolet Silverado Code
1. What does the OBDII code P18BB mean for a 2016 Chevrolet Silverado?
Code P18BB indicates an issue with the Internal Mode Switch (IMS) 'B' circuit, which is stuck off and reporting an invalid voltage range.
2. What are the symptoms of code P18BB in a 2016 Chevrolet Silverado?
Common symptoms include difficulty shifting gears, transmission stuck in one gear, poor drivability, and the check engine light being illuminated.
3. What causes the P18BB code to appear in a Chevrolet Silverado?
Potential causes include a faulty Internal Mode Switch, damaged wiring or connectors in the IMS circuit, or a malfunctioning transmission control module (TCM).
4. How is the P18BB code diagnosed?
A mechanic will use a scan tool to confirm the code, inspect the IMS wiring and connectors for damage, test the voltage and continuity of the circuit, and check the functionality of the IMS and TCM.
5. Can I drive my 2016 Chevrolet Silverado with the P18BB code?
Driving with this code is not recommended as it can lead to transmission issues, reduced performance, and further damage if not addressed.
6. How do you fix the P18BB code on a Chevrolet Silverado?
Repairs may include replacing the Internal Mode Switch, repairing or replacing damaged wiring, or reprogramming or replacing the transmission control module (TCM) if necessary.
7. What is the Internal Mode Switch in a Chevrolet Silverado?
The Internal Mode Switch is a sensor within the transmission that monitors gear positions and sends data to the TCM to regulate shifting.
8. How much does it cost to fix a P18BB code on a 2016 Chevrolet Silverado?
Repair costs vary depending on the severity of the issue, but replacing the IMS typically costs $200–$500, including parts and labor.
9. Can a low battery cause the P18BB code in a Chevrolet Silverado?
While unlikely, a low or failing battery can sometimes cause electronic faults, so it’s worth checking the battery and charging system during diagnosis.
10. How can I prevent the P18BB code from occurring again?
Regular maintenance, inspecting wiring for damage, and addressing transmission issues promptly can help prevent this code from reappearing.
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