Easy one-page printout for the garage or repair shop
This summary uses the existing diagnostic information shown in full below.
This code means that the car's computer is detecting a problem with the gear shifter. It's like when your remote control doesn't work because the batteries are not in right or there's a loose wire.
The P1820 code indicates that there is a high voltage condition in the gear selector lever circuit, which can affect the transmission's ability to shift gears properly.
The P1820 code is triggered when the Powertrain Control Module (PCM) detects a higher than expected voltage in the Gear Selector Lever (GSL1) circuit. This circuit is responsible for communicating the position of the gear selector to the transmission control system.
• Check Engine Light is on
• Transmission may not shift properly
• Vehicle may not start or move
• Faulty gear selector lever
• Damaged wiring or connectors in the GSL1 circuit
• Faulty transmission range sensor
PCM: Powertrain Control Module
GSL1: Gear Selector Lever 1
• Use an OBD-II scanner to confirm the code
• Inspect the gear selector lever for damage
• Check the wiring and connectors in the GSL1 circuit
• Replace the faulty gear selector lever
• Repair or replace damaged wiring and connectors
• Replace the transmission range sensor if faulty
• OBD-II scanner
• Multimeter
• Socket set
$150 - $400
Moderate
• Chevrolet Silverado
• GMC Sierra
• Cadillac Escalade
• Regularly inspect the gear selector lever and its wiring
• Ensure proper maintenance of the transmission system
• Avoid forcing the gear shifter
Sensor Issue
• Do not drive the vehicle until the issue is resolved to prevent further damage
• Consult with a professional mechanic for an accurate diagnosis
Check with the vehicle manufacturer for warranty coverage on transmission components.
The P1820 code has been associated with vehicles equipped with electronic transmission control systems and has been reported in models from the early 2000s onwards.
High – This issue can prevent the vehicle from being driven safely.
Driving with a malfunctioning gear selector can be dangerous and may lead to accidents. Always address this issue promptly.
• Vehicle must be in park or neutral
• Engine must be running
The gear selector lever is typically located between the driver and passenger seats or on the steering column, depending on the vehicle model.
Q: Can I drive with a P1820 code?
A: It's not recommended to drive with this code as it can affect gear shifting and vehicle safety.
Q: How do I clear a P1820 code?
A: After repairing the issue, you can clear the code with an OBD-II scanner, but it will return if the problem persists.
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