P0973 - PCM detects an open or short to ground in the 1-2 SS valve circuit

The diagnostic trouble code (DTC) P0973 indicates that the Powertrain Control Module (PCM) has detected a fault in the 1-2 Shift Solenoid (SS) valve control circuit, specifically an open circuit or a short to ground. This malfunction can lead to noticeable issues with the vehicle's transmission performance, affecting shift quality and overall drivability. Addressing this code promptly is crucial to prevent further damage to the transmission.

P0973 Code: Comprehensive Overview

Aspect	Description	Possible Causes
Definition	PCM detects an open or short to ground in the 1-2 Shift Solenoid (SS) valve circuit.	Faulty 1-2 Shift Solenoid: The solenoid itself may be defective, causing an open or short. Wiring Issues: Damaged, corroded, or loose wiring in the solenoid circuit. Connector Problems: Corroded or damaged connectors at the solenoid or PCM. PCM Failure: In rare cases, a faulty PCM can misinterpret signals or generate false codes. Low Transmission Fluid: Insufficient fluid can cause erratic solenoid operation. Internal Transmission Damage: Physical damage to the transmission can affect solenoid function.
Symptoms	Harsh or erratic 1-2 shift, Failure to shift into 2nd gear, Transmission slipping, Limp mode (transmission stuck in a single gear), Increased fuel consumption, Illuminated Check Engine Light.
Diagnostic Steps	Verify the code with a scanner, Inspect wiring and connectors for damage, Test the 1-2 shift solenoid for resistance and continuity, Check transmission fluid level and condition, Monitor solenoid operation with a scan tool, Perform a PCM output circuit test.
Potential Solutions	Replace the faulty 1-2 shift solenoid, Repair or replace damaged wiring and connectors, Flush and refill transmission fluid, Replace the PCM (rare), Repair internal transmission damage (if applicable).
Related Codes	P0750 (Shift Solenoid A Malfunction), P0751 (Shift Solenoid A Performance or Stuck Off), P0752 (Shift Solenoid A Stuck On), P0970 (Shift Solenoid A Control Circuit High), P0971 (Shift Solenoid B Control Circuit Range/Performance), P0974 (Shift Solenoid B Control Circuit Low).
Impact on Drivability	Significant impact. Harsh shifting or complete failure to shift properly can make the vehicle unsafe to drive. Limp mode limits speed and acceleration.
Importance of Addressing	High importance. Ignoring this code can lead to further transmission damage, more costly repairs, and potential safety hazards.
Tools Needed for Diagnosis	OBD-II scanner, Multimeter, Wiring diagram for the vehicle, Jumper wires, Transmission fluid dipstick.
Safety Precautions	Disconnect the negative battery cable before working on electrical components. Allow the engine and exhaust system to cool down before working near them. Use caution when working with transmission fluid, as it can be hot.
Typical Repair Costs	Varies widely depending on the cause. Solenoid replacement can range from $150 to $500. Wiring repairs may cost $100 to $300. PCM replacement can be more expensive, potentially ranging from $500 to $1500. Internal transmission repairs can be the most costly, potentially exceeding $2000.

Detailed Explanations

Definition: The P0973 code signifies that the PCM has detected a low voltage or a ground fault in the control circuit for the 1-2 Shift Solenoid valve. This means the PCM is either not seeing the expected voltage signal or is detecting an unintended path to ground in the circuit. This typically happens due to a damaged solenoid, wiring, or connector.

Symptoms: The most common symptom is a noticeable issue with the 1-2 shift. This can manifest as a harsh or erratic shift, a failure to shift into second gear at all, or transmission slipping during the shift. The vehicle might also enter limp mode, restricting it to a single gear to protect the transmission. Other symptoms include increased fuel consumption and the Check Engine Light being illuminated.

Diagnostic Steps: The first step is to verify the code using an OBD-II scanner. Then, a thorough visual inspection of the wiring and connectors associated with the 1-2 shift solenoid is crucial to look for any signs of damage, corrosion, or loose connections. The solenoid itself should be tested for proper resistance and continuity using a multimeter. Checking the transmission fluid level and condition is also important, as low or contaminated fluid can affect solenoid operation. A scan tool can be used to monitor the solenoid's operation while driving. Finally, a PCM output circuit test can help determine if the PCM is sending the correct signals to the solenoid.

Potential Solutions: The most common solution is to replace the faulty 1-2 shift solenoid. If the problem is with the wiring or connectors, repairing or replacing the damaged components is necessary. A transmission fluid flush and refill might be needed if the fluid is contaminated. In rare cases, PCM replacement might be required if it's determined to be the source of the problem. If the diagnostic process reveals internal transmission damage, a more extensive repair or even a transmission rebuild might be necessary.

Related Codes: Several other codes can be related to transmission solenoid issues. These include: P0750 (Shift Solenoid A Malfunction), P0751 (Shift Solenoid A Performance or Stuck Off), P0752 (Shift Solenoid A Stuck On), P0970 (Shift Solenoid A Control Circuit High), P0971 (Shift Solenoid B Control Circuit Range/Performance), and P0974 (Shift Solenoid B Control Circuit Low). Understanding these codes can help pinpoint the specific problem within the transmission control system.

Impact on Drivability: The impact on drivability is significant. A faulty 1-2 shift solenoid can cause harsh shifting or complete failure to shift properly, making the vehicle unsafe to drive, especially in traffic. Limp mode severely limits speed and acceleration, further restricting drivability.

Importance of Addressing: It is highly important to address the P0973 code promptly. Ignoring this code can lead to further transmission damage, resulting in more costly repairs. It can also create potential safety hazards due to unpredictable shifting behavior.

Tools Needed for Diagnosis: The necessary tools include an OBD-II scanner to read the code, a multimeter to test electrical circuits, a wiring diagram specific to the vehicle to trace the solenoid circuit, jumper wires for testing, and a transmission fluid dipstick to check the fluid level and condition.

Safety Precautions: Always disconnect the negative battery cable before working on electrical components to prevent shorts. Allow the engine and exhaust system to cool down before working near them to avoid burns. Use caution when working with transmission fluid, as it can be hot.

Typical Repair Costs: Repair costs can vary widely. Replacing a solenoid itself might range from $150 to $500, depending on the vehicle and the labor involved. Wiring repairs are typically less expensive, ranging from $100 to $300. PCM replacement can be significantly more expensive, potentially costing $500 to $1500 or more. Internal transmission repairs are the most costly, potentially exceeding $2000, especially if a rebuild is required.

Frequently Asked Questions

What does the P0973 code mean? It means the PCM has detected an open circuit or a short to ground in the 1-2 shift solenoid control circuit. This indicates a problem with the electrical circuit controlling the solenoid.
Can I drive my car with a P0973 code? It's not recommended. The transmission may not shift properly, potentially causing damage and safety issues.
What are the common causes of a P0973 code? Common causes include a faulty 1-2 shift solenoid, damaged wiring, corroded connectors, or a faulty PCM. Low transmission fluid can also contribute.
How do I fix a P0973 code? Possible fixes include replacing the solenoid, repairing wiring, cleaning or replacing connectors, or replacing the PCM (rare). Always diagnose the root cause first.
Is the P0973 code serious? Yes, it's a serious code because it can lead to further transmission damage and potential safety hazards. Prompt diagnosis and repair are recommended.

Conclusion

The P0973 code indicates a fault in the 1-2 shift solenoid circuit, likely due to a faulty solenoid, wiring issues, or a PCM problem. Proper diagnosis and repair are crucial to restore proper transmission function and prevent further damage.