P1903 - Kickdown Solenoid Circuit Low Voltage
The P1903 code indicates that the powertrain control module (PCM) has detected a low voltage condition in the kickdown solenoid circuit. This solenoid is responsible for initiating a downshift when the accelerator pedal is fully depressed, allowing for maximum acceleration. Low voltage can result from a faulty solenoid, damaged wiring, poor electrical connections, or a failing PCM. This issue can lead to improper transmission operation, such as delayed or harsh downshifts, and may affect vehicle performance.
1. Symptoms You Will Notice
- Check Engine Light illuminated
- Delayed or harsh downshifts when accelerating
- Transmission stuck in a single gear
- Reduced fuel economy
2. Most Common Causes
- Faulty kickdown solenoid
- Damaged or corroded wiring/connectors in the solenoid circuit
- Low battery voltage or charging system issues
- Faulty PCM (rare)
3. Step-by-Step Diagnosis
Step 1: Use an OBD2 scanner to confirm the code and check for additional transmission-related codes.
Step 2: Visually inspect the kickdown solenoid wiring and connectors for damage, corrosion, or loose connections.
Step 3: Test the solenoid resistance with a multimeter (specifications vary by vehicle; typically 10-30 ohms).
Step 4: Check battery voltage and charging system output to ensure proper voltage supply.
Step 5: If all else is fine, test the PCM output to the solenoid and replace the PCM if necessary.
4. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive with this code as it can cause unpredictable transmission behavior, potentially leading to unsafe driving conditions or further transmission damage.
How much does it cost to fix?▼
The cost typically ranges from $50 to $150 for parts and labor, depending on whether the solenoid or wiring needs replacement. PCM replacement can be more expensive.
5. Commonly Affected Makes
This is a manufacturer-specific code. The exact manufacturer is not confirmed in our current database.