Shift Solenoid Control Circuit High Voltage
The P099F code indicates that the powertrain control module (PCM) has detected a voltage higher than the specified range in the shift solenoid control circuit. This solenoid is responsible for directing transmission fluid to engage the correct gear. A high voltage condition can be caused by a short to power, a faulty solenoid, or an internal PCM issue. This can lead to erratic shifting, transmission slippage, or failure to shift, potentially causing transmission damage if ignored.
01. Most Common Causes
- Short to power in the shift solenoid circuit
- Faulty shift solenoid
- Damaged wiring or connector
- Failed PCM
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Erratic or harsh shifting
- Transmission stuck in gear
- 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 and connectors for damage or corrosion.
Step 3: Test the shift solenoid resistance and compare to manufacturer specs.
Step 4: Check for voltage at the solenoid connector with key on; if high, trace short to power.
Step 5: If wiring and solenoid are good, suspect PCM failure and perform further diagnostics.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended. Driving with a high voltage condition can cause transmission damage or sudden loss of drive. Have the vehicle inspected immediately.
How much does it cost to fix?▼
Repair costs typically range from $150 to $400, depending on the cause. A solenoid replacement may cost $150-$300, while PCM replacement can exceed $500.