Shift Solenoid Control Circuit Low
The P0985 code indicates that the Powertrain Control Module (PCM) has detected a low voltage condition in the control circuit of the shift solenoid 'E' (or a specific solenoid depending on the vehicle). This solenoid is responsible for directing transmission fluid to engage specific gears. A low voltage reading suggests a short to ground, open circuit, or faulty solenoid, which can lead to improper transmission operation.
01. Most Common Causes
- Faulty shift solenoid
- Damaged wiring or connectors in the solenoid circuit
- Low transmission fluid level or dirty fluid
- Internal transmission mechanical failure
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Harsh or erratic shifting
- Transmission stuck in a single gear (limp mode)
- Decreased fuel economy
03. Step-by-Step Diagnosis
Step 1: Scan for codes and note freeze frame data.
Step 2: Inspect transmission fluid level and condition; top off or replace if necessary.
Step 3: Visually check wiring and connectors for damage, corrosion, or loose connections.
Step 4: Test solenoid resistance with a multimeter and compare to manufacturer specs.
Step 5: Check for shorts to ground or power in the control circuit.
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 fail, potentially causing further damage.
How much does it cost to fix?▼
The cost typically ranges from $50 to $150 for diagnosis and solenoid replacement, but can be higher if internal transmission repairs are needed.