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 a sensor in your car is detecting that a part called the turbine shaft is spinning too fast. It's like when a toy top spins too quickly and starts wobbling.
The code P18AC indicates that the input or turbine shaft speed sensor 'A' is detecting a speed that exceeds the expected range.
The input/turbine shaft speed sensor 'A' monitors the rotational speed of the turbine shaft in the transmission. If the sensor detects a speed that is beyond the normal operating range, the engine control module (ECM) triggers the P18AC code. This could be due to a faulty sensor, wiring issues, or actual mechanical problems causing the shaft to overspeed.
• Check Engine Light is on
• Transmission shifting issues
• Unusual noises from the transmission
• Faulty input/turbine shaft speed sensor
• Wiring or connector issues
• Mechanical problems in the transmission
ECM: Engine Control Module
OBD-II: On-Board Diagnostics, Second Generation
• Use an OBD-II scanner to confirm the code.
• Inspect the wiring and connectors for the sensor.
• Test the sensor for proper operation.
• Replace the faulty speed sensor.
• Repair or replace damaged wiring or connectors.
• Inspect and repair any mechanical issues in the transmission.
• OBD-II scanner
• Multimeter
• Basic hand tools
$150 - $400
Moderate
• Chevrolet Malibu
• Ford Focus
• Honda Accord
• Regular transmission maintenance
• Ensure proper fluid levels
• Inspect wiring and connectors periodically
Sensor Issue
• Avoid driving at high speeds until the issue is resolved.
• Consult a professional mechanic for a thorough diagnosis.
Check with your vehicle manufacturer for warranty coverage on transmission components.
This code has been associated with sensor failures and wiring issues in various models over the years.
Moderate – It is advisable to address this issue soon to prevent potential transmission damage.
Driving with a malfunctioning transmission sensor can lead to unsafe driving conditions. Address the issue promptly.
• Vehicle at operating temperature
• Transmission in gear
The input/turbine shaft speed sensor is typically located on the transmission housing.
Q: What happens if I ignore this code?
A: Ignoring this code can lead to transmission damage and unsafe driving conditions.
Q: Can I still drive my car with this code?
A: It's possible, but not recommended. Driving with this issue can lead to further damage.
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