Shift Solenoid 'E' Control Circuit Low
The P0985 code indicates that the Powertrain Control Module (PCM) has detected a low voltage condition in the control circuit of shift solenoid 'E'. This solenoid is responsible for directing hydraulic fluid 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, transmission slippage, or failure to shift. Common causes include damaged wiring, corroded connectors, a defective solenoid, or a failing PCM.
1. Symptoms You Will Notice
- Check Engine Light illuminated
- Harsh or erratic shifting
- Transmission stuck in gear or fails to shift
- Reduced fuel economy
- Transmission slipping
2. Most Common Causes
- Faulty shift solenoid 'E' (internal coil open)
- Open circuit in the signal wire (power or ground) between the TCM/PCM and the solenoid
- Short to ground in the solenoid control wire
- Damaged, corroded, or loose connector at the solenoid or TCM/PCM
- Blown fuse in the solenoid power supply circuit
- Defective transmission control module (TCM) or PCM (internal driver failure)
3. Step-by-Step Diagnosis
Step 1: Scan for codes and record 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; compare to manufacturer specs.
Step 5: Check for power and ground at solenoid connector with ignition on.
Step 6: If wiring and solenoid are good, test PCM output or replace PCM.
4. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended. Driving with a low voltage solenoid circuit can cause erratic shifting, transmission damage, or complete failure. Have it diagnosed and repaired promptly.
How much does it cost to fix?▼
The cost typically ranges from $50 to $150 for DIY solenoid replacement, or $200 to $500 at a shop including labor and diagnostics.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.