Shift Solenoid Control Circuit Low
The P0973 code indicates that the Powertrain Control Module (PCM) has detected a low voltage condition in the control circuit of shift solenoid 'A' (or a specific solenoid depending on the vehicle). This solenoid is responsible for regulating hydraulic pressure to engage specific gears in the automatic transmission. A low voltage reading suggests a short to ground, open circuit, or faulty solenoid, which can lead to improper shifting or transmission slippage.
01. Most Common Causes
- Faulty shift solenoid
- Short to ground in solenoid control circuit
- Open circuit in solenoid wiring or connector
- Corroded or damaged wiring harness
- Failed PCM (rare)
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Harsh or erratic shifting
- Transmission stuck in a single gear (limp mode)
- Delayed engagement when shifting into drive or reverse
- Decreased fuel economy
03. Step-by-Step Diagnosis
Step 1: Scan for additional codes and record freeze frame data.
Step 2: Visually inspect the transmission wiring harness and connectors for damage, corrosion, or loose connections.
Step 3: Using a multimeter, check the resistance of the shift solenoid (typically 10-30 ohms). Compare to manufacturer specs.
Step 4: Test the control circuit for shorts to ground or power by disconnecting the PCM and solenoid connector.
Step 5: If wiring and solenoid are okay, check for PCM issues by monitoring voltage output with a scan tool.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive long distances as the transmission may shift erratically or enter limp mode, potentially causing further damage.
How much does it cost to fix?▼
Repair costs typically range from $150 to $400, including parts and labor, depending on whether the solenoid or wiring needs replacement.