Shift Solenoid Control Circuit High
The P0986 code indicates that the powertrain control module (PCM) has detected a high voltage condition in the control circuit of the shift solenoid. This solenoid is responsible for regulating hydraulic pressure to engage specific gears in the automatic transmission. A high voltage reading typically points to a short to power, a faulty solenoid, or an internal PCM issue, which can lead to improper shifting or transmission damage.
01. Most Common Causes
- Short to power in the solenoid control circuit
- Faulty shift solenoid
- Damaged wiring or connector
- Internal PCM failure
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Harsh or erratic shifting
- Transmission stuck in gear
- Reduced fuel economy
03. Step-by-Step Diagnosis
Step 1: Scan for codes and record freeze frame data.
Step 2: Visually inspect wiring and connectors for damage or corrosion.
Step 3: Test solenoid resistance with a multimeter (typically 10-30 ohms).
Step 4: Check for voltage at the solenoid connector with key on (should be battery voltage).
Step 5: If wiring and solenoid are okay, test PCM output or replace PCM.
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 unsafe shifting. Have it diagnosed promptly.
How much does it cost to fix?▼
Repair costs typically range from $50 to $150 for a solenoid replacement, but can be higher if wiring repairs or PCM replacement is needed.