P2738: Pressure Control Solenoid 'H' Control Circuit Low
The Powertrain Control Module (PCM) has detected a low voltage condition in the control circuit of the pressure control solenoid 'H'. This solenoid is typically part of the transmission's hydraulic control system, regulating line pressure or clutch pressure. A low circuit voltage indicates a short to ground, open circuit, or faulty solenoid, which can cause erratic shifting, slipping, or harsh engagement.
1. Most Common Causes
- Faulty pressure control solenoid 'H'
- Open or shorted wiring in solenoid control circuit
- Poor electrical connection at solenoid or PCM
- Failed PCM (rare)
2. Symptoms You Will Notice
- Check Engine Light illuminated
- Harsh or delayed shifts
- Transmission slipping
- Transmission stuck in limp mode
3. Step-by-Step Diagnosis
Step 1: Scan for additional codes and record freeze frame data.
Step 2: Inspect wiring and connectors for damage, corrosion, or loose pins.
Step 3: Measure resistance of solenoid 'H' and compare to specs (typically 5-20 ohms).
Step 4: Check for voltage and ground at solenoid connector with ignition on.
Step 5: Perform a solenoid actuation test using a scan tool to verify operation.
4. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended. Driving with a low circuit condition can cause transmission damage due to improper pressure control. You may experience harsh shifting or slipping, which can worsen over time.
How much does it cost to fix?▼
Repair costs typically range from $150 to $400, including parts and labor. A solenoid replacement is around $100-$200, plus diagnostic time and fluid service if needed.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.