Easy one-page printout for the garage or repair shop
This summary uses the existing diagnostic information shown in full below.
The car's computer is having trouble reading how fast the engine is spinning.
This code indicates that the Transmission Control Module (TCM) is detecting a low voltage signal from the engine speed output circuit.
The P0738 code is triggered when the TCM detects a voltage level in the engine speed output circuit that is lower than expected. This circuit is responsible for sending information about the engine's RPM to the TCM, which is crucial for proper transmission operation.
• Check Engine Light is on
• Transmission may not shift properly
• Poor fuel economy
• Faulty engine speed sensor
• Wiring issues such as shorts or opens in the circuit
• Malfunctioning TCM
TCM: Transmission Control Module
RPM: Revolutions Per Minute
• Scan the vehicle for additional trouble codes.
• Inspect the wiring and connectors related to the engine speed sensor.
• Test the engine speed sensor for proper operation.
• Repair or replace damaged wiring or connectors.
• Replace the engine speed sensor if faulty.
• Replace or reprogram the TCM if necessary.
• OBD-II scanner
• Multimeter
• Basic hand tools
$150 - $500
Moderate
• Honda Accord
• Toyota Camry
• Ford F-150
• Regularly inspect and maintain vehicle wiring and connectors.
• Ensure timely replacement of sensors as per manufacturer guidelines.
• Keep the vehicle's software updated.
Sensor Issue
• Avoid driving the vehicle if it is not shifting properly.
• Consult a professional mechanic for a thorough diagnosis.
Check if the vehicle's powertrain warranty covers sensor issues.
This code is more common in vehicles with higher mileage or those that have experienced transmission issues in the past.
Moderate – Addressing this issue promptly can prevent further transmission damage.
Driving with a malfunctioning transmission can be unsafe and may lead to further vehicle damage.
• Vehicle must be driven to replicate the issue.
• Ensure the engine is at operating temperature.
The engine speed sensor is typically located on the engine block or near the crankshaft.
Q: Can I drive with a P0738 code?
A: It's not recommended to drive with this code, as it can lead to transmission issues.
Q: How do I reset the P0738 code?
A: After repairs, use an OBD-II scanner to clear the code, but ensure the issue is resolved first.
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