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 something inside the car's brain for controlling the gears is not working right. It's like when a remote control has a button that doesn't work properly.
The Transmission Control Module (TCM) is responsible for managing the transmission's operations. This code indicates a fault within a specific component of the TCM, labeled as CG122, which could affect the transmission's performance.
The P171F code is triggered when the Transmission Control Module (TCM) detects an internal fault in one of its components, specifically the CG122 component. This could be due to a hardware malfunction, software issue, or communication error within the module.
• Check Engine Light is on
• Transmission may not shift properly
• Vehicle may enter limp mode
• Faulty Transmission Control Module (TCM)
• Software glitch in the TCM
• Wiring or connector issues related to the TCM
Transmission Control Module (TCM): A computer that controls the transmission's functions.
Limp Mode: A safety feature that limits the vehicle's performance to prevent damage.
• Use an OBD-II scanner to confirm the P171F code.
• Inspect the TCM and related wiring for damage or loose connections.
• Check for any software updates for the TCM.
• Reprogram or update the TCM software.
• Repair or replace damaged wiring or connectors.
• Replace the Transmission Control Module if necessary.
• OBD-II scanner
• Multimeter
• Basic hand tools
$300 - $1200
Moderate
• Ford Focus
• Chevrolet Malibu
• Honda Accord
• Regularly update vehicle software.
• Inspect transmission wiring for wear.
• Avoid harsh driving conditions.
Transmission Control Module Issue
• Avoid driving at high speeds until the issue is resolved.
• Consult a professional mechanic for a thorough diagnosis.
Check if the vehicle's powertrain warranty covers TCM repairs or replacements.
This code has been associated with transmission control issues in vehicles with electronic control systems.
Moderate – It should be addressed soon to avoid potential transmission damage.
Driving with a faulty transmission control module can lead to unsafe driving conditions.
• Vehicle must be in a safe, stationary position.
• Ensure the engine is off before inspecting components.
The Transmission Control Module is typically located near the transmission or under the hood in the engine bay.
Q: Can I drive my car with a P171F code?
A: It's best to avoid driving until the issue is fixed, as it can lead to further transmission damage.
Q: How do I reset the TCM?
A: Disconnect the battery for a few minutes or use an OBD-II scanner to clear the code, but ensure the issue is fixed first.
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