Shift Solenoid Control Circuit Low Voltage
The P099E code indicates that the powertrain control module (PCM) has detected a low voltage condition in the control circuit of a specific shift solenoid. This solenoid is responsible for regulating hydraulic pressure to engage the correct gear. A low voltage reading suggests an electrical fault, such as a short to ground, open circuit, or failed solenoid, which can prevent proper transmission operation.
1. Symptoms You Will Notice
- Check Engine Light illuminated
- Harsh or erratic shifting
- Transmission stuck in a single gear (limp mode)
- Decreased fuel economy
2. Most Common Causes
- Faulty shift solenoid 'H' with altered internal resistance
- Short to ground in the solenoid control circuit wiring
- Loose connection or corrosion at solenoid connectors
- Excessive resistance in the wiring harness to the solenoid
- Internal TCM failure (less common)
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 the shift solenoid resistance with a multimeter (compare to specs).
Step 5: Check for voltage at the solenoid connector with the ignition on; if low, trace circuit for shorts or opens.
4. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended. Driving with a low voltage condition can cause further transmission damage and may leave you stranded.
How much does it cost to fix?▼
Repair costs typically range from $150 to $400, depending on whether the solenoid, wiring, or fluid needs attention.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.