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 there is a problem with a part in your car that helps it change gears. It's like when a toy robot can't move its arm because a wire is loose.
The P1803 code indicates that the transmission control module (TCM) has detected a low voltage condition in the circuit for shift solenoid 'C'.
Shift solenoids are responsible for controlling the flow of transmission fluid in automatic transmissions, allowing the vehicle to change gears. The 'C' solenoid is one of several solenoids, and a 'circuit low' condition means that the electrical circuit has lower than expected voltage, possibly due to a short or open circuit.
• Transmission not shifting properly
• Check Engine Light on
• Poor fuel economy
• Faulty shift solenoid 'C'
• Wiring issues such as a short or open circuit
• Faulty transmission control module (TCM)
Transmission Control Module (TCM): A computer that controls the transmission functions.
Shift Solenoid: A component that controls the flow of transmission fluid to change gears.
• Use an OBD-II scanner to confirm the code.
• Inspect the wiring and connectors to the shift solenoid 'C'.
• Test the shift solenoid 'C' for proper operation and resistance.
• Replace the faulty shift solenoid 'C'.
• Repair or replace damaged wiring or connectors.
• Replace the transmission control module if necessary.
• OBD-II scanner
• Multimeter
• Wrench set
$150 - $400
Moderate
• Ford F-150
• Chevrolet Silverado
• Toyota Camry
• Regular transmission fluid changes
• Routine inspection of transmission wiring
• Avoiding harsh driving conditions
Transmission Issue
• Avoid driving the vehicle until repaired to prevent further damage.
• Consult a professional mechanic for proper diagnosis and repair.
Check vehicle warranty for coverage on transmission components.
This code has been associated with issues in vehicles with high mileage or those that have not had regular transmission maintenance.
Moderate – It is advisable to address this issue soon to avoid potential transmission damage.
Driving with a malfunctioning transmission can be dangerous and may lead to further vehicle damage.
• Engine at operating temperature
• Vehicle in drive mode
The shift solenoid 'C' is located inside the transmission, usually accessible by removing the transmission pan.
Q: Can I drive with a P1803 code?
A: It's not recommended to drive with this code as it can lead to further transmission damage.
Q: How do I reset the P1803 code?
A: After repairs, you can use an OBD-II scanner to clear the code, but it may return if the issue is not fixed.
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