Definition of Code P0973
Fault code P0973 detects an error with the shift solenoid A control circuit.
What Does Code P0973 Mean?
Code P0973 is a generic fault code that indicates a problem with shift solenoid A. Shift solenoids are controlled by the Transmission Control Module (TCM) and are activated and deactivated to change gear ratios and allow smooth shifting in the automatic transmission. Depending on the vehicle’s make and model, shift solenoid valve A may control the transmission’s clutches, brakes, or bands. When the TCM detects abnormal readings from the shift solenoid, the control circuit will be shut down, and the Powertrain Control Module (PCM) will store fault code P0973.
What Causes Code P0973?
Fault code P0973 can be caused by several different things:
- Faulty shift solenoid A
- Damaged wires or connectors in the system
- Defective control circuit
- Low or dirty transmission fluid
- In rare cases, a faulty TCM, PCM, or Engine Control Module (ECM)
What Are the Symptoms of Code P0973?
When code P0973 is detected, the vehicle’s check engine light will likely illuminate on the dashboard. The vehicle may experience difficulty or inability to shift into certain gears, leading to driving issues such as harsh shifting and uneven acceleration. It is also common for fuel efficiency to decrease.
How Does a Mechanic Diagnose Code P0973?
Code P0973 will be addressed using a standard OBD-II fault code scanner. A reputable technician will review freeze frame data to assess the code and check for additional codes. If multiple fault codes are detected, they should be inspected in the order they appear on the scanner. The fault codes will then be reset, and the vehicle restarted so the mechanic can see if the code remains detected. If the code disappears, it is most likely the result of an intermittent error or possibly a false detection.
If the code persists, the mechanic will need to visually inspect the transmission’s electrical components. Wires and connectors should be checked for short circuits, open circuits, or damage and replaced if necessary. The transmission fluid will then be checked, with low levels topped up and dirty fluid replaced. If the transmission fluid is extremely contaminated, there is likely a more serious issue with the transmission, which may require rebuilding or replacement.
A digital volt/ohmmeter can then be used to identify the circuit corresponding to shift solenoid valve A, and the solenoid, circuit, and harness can all be tested.
After any replacements, the mechanic will need to reset the fault codes again, restart the vehicle, and check if the code remains detected. This will help the mechanic know as soon as the issue is resolved.
Common Mistakes When Diagnosing Code P0973
The most frequent mistake when evaluating code P0973 comes from not following the OBD-II fault code diagnostic protocol. Mechanics must adhere to the protocol throughout the inspection to ensure effective diagnosis and repairs. It is quite common for the shift solenoid to be mistakenly replaced when the actual problem was faulty wiring or insufficient transmission fluid.
How Severe Is Code P0973?
Usually, a vehicle with fault code P0973 will still be drivable, although the driver will likely experience transmission issues. Ignoring code P0973 can lead to severe transmission damage, so the vehicle should always be inspected when the code is detected.
What Repairs Can Fix Code P0973?
Possible repairs for fault code P0973 are:
- Replacement of shift solenoid A
- Replacement of wires, connectors, circuits, or harness
- Adding or replacing transmission fluid
- In rare cases, replacement of the PCM, TCM, or ECM