The P1390 trouble code is a diagnostic trouble code (DTC) that indicates a problem with the timing belt or the relationship between the camshaft and crankshaft position sensors. This code is prevalent in various vehicles and typically points to issues such as a skipped timing belt tooth or problems with the throttle/pedal position sensor circuit. When the P1390 code is triggered, it can lead to performance issues, rough idling, or even engine stalling, prompting vehicle owners to seek immediate attention.
P1390 Code Meaning | P1390 Code Common Causes |
---|---|
Timing Belt Skipped One Tooth or More | Improperly installed timing belt |
Throttle/Pedal Position Sensor/Switch A Circuit Intermittent | Faulty throttle position sensor |
Crankshaft Position Sensor A Circuit Malfunction | Bad crankshaft position sensor |
Shift Solenoid E Performance or Stuck Off | Transmission issues related to solenoids |
Fuel and Air Metering Issues | Dirty mass airflow (MAF) sensor |
Symptoms of P1390 Code
When the P1390 code is triggered, several symptoms may be observed:
- Check Engine Light: The most common indication is the illumination of the check engine light on the dashboard.
- Rough Idling: The vehicle may experience irregular idling or stalling, particularly during acceleration.
- Poor Acceleration: Drivers may notice a decrease in engine performance and responsiveness.
- Increased Fuel Consumption: The vehicle may consume more fuel than usual due to inefficient engine operation.
- Engine Misfires: Misfiring can occur if the timing is significantly off.
Technical Explanation
The P1390 code relates primarily to the synchronization between the crankshaft and camshaft. These components must work in harmony for optimal engine performance. The crankshaft position sensor monitors the position of the crankshaft, while the camshaft position sensor tracks the camshaft’s position. If there is a discrepancy between these signals—often due to a timing belt that has skipped a tooth—this code will be generated.
Causes of P1390 Code
- Timing Belt Issues: A skipped tooth on the timing belt can disrupt the synchronization of engine components.
- Sensor Malfunctions: Faulty crankshaft or camshaft position sensors can lead to incorrect readings.
- Wiring Problems: Damaged wiring or poor connections can cause intermittent signals that trigger this code.
- Throttle Position Sensor Faults: Issues with the throttle/pedal position sensor can also lead to this DTC being set.
- Mechanical Timing Issues: If the mechanical timing of the engine has been altered due to maintenance or repairs, it may cause this error.
Step-by-Step Diagnosis
Diagnosing a P1390 code involves several steps:
- Scan for Codes: Use an OBD-II scanner to confirm that P1390 is present along with any other related codes.
- Visual Inspection: Check for any visible signs of damage in wiring and connectors related to the crankshaft and camshaft sensors.
- Check Timing Belt Alignment:
- Remove any covers necessary to access the timing belt.
- Inspect the alignment marks on both the crankshaft and camshaft sprockets.
- If misaligned, replace or adjust the timing belt as needed.
- Test Sensors:
- Use a multimeter to test the resistance and output voltage of both crankshaft and camshaft sensors.
- Replace any faulty sensors.
- Inspect Throttle Position Sensor:
- Check for proper operation using an OBD-II scanner.
- If necessary, replace the throttle position sensor.
- Clear Codes and Test Drive: After repairs, clear any codes and take the vehicle for a test drive to see if the P1390 code reappears.
Solution Methods
Timing Belt Replacement
If it’s determined that the timing belt has skipped teeth, follow these steps:
- Gather Tools and Parts:
- Timing belt kit (includes tensioner)
- Basic hand tools (sockets, wrenches)
- Torque wrench
- Remove Necessary Components:
- Disconnect battery.
- Remove any components obstructing access to the timing belt (e.g., covers, pulleys).
- Replace Timing Belt:
- Align all timing marks correctly.
- Install new timing belt and tensioner according to manufacturer specifications.
- Reassemble Components:
- Reinstall all removed components in reverse order.
- Reconnect Battery and Test:
- Start engine and check for proper operation.
Sensor Replacement
If faulty sensors are identified:
- Disconnect Battery.
- Remove Old Sensor:
- Locate and remove faulty crankshaft or camshaft sensor.
- Install New Sensor:
- Install new sensor ensuring proper alignment and connection.
- Reconnect Battery and Test Drive.
Cost Estimates
- Timing Belt Replacement: Typically ranges from $500 to $1,000 depending on labor rates and vehicle make/model.
- Sensor Replacement Costs:
- Crankshaft Position Sensor: $50-$150
- Camshaft Position Sensor: $50-$150
- Throttle Position Sensor: $30-$100
Labor costs can vary widely based on location, but expect around $75-$150 per hour at most repair shops.
Warnings and Recommendations
- Always consult your vehicle’s service manual for specific instructions related to your make and model.
- If you are not comfortable performing these repairs yourself, seek assistance from a qualified mechanic.
- Ignoring a P1390 code can lead to more severe engine damage over time; timely diagnosis and repair are crucial.
Closing Paragraph
The P1390 trouble code can signal significant issues within your vehicle’s engine management system, particularly concerning timing synchronization between critical components like the crankshaft and camshaft sensors. Understanding this code’s implications allows vehicle owners and DIY mechanics to take proactive steps toward diagnosis and repair. By following proper diagnostic procedures and addressing underlying issues promptly, you can ensure your vehicle operates smoothly while avoiding costly repairs down the line.
Frequently Asked Questions About P1390
- What does P1390 mean?
P1390 indicates that there is an issue with timing synchronization in your engine, often due to a skipped timing belt tooth. - Can I drive my car with a P1390 code?
It is not advisable to drive with this code as it may lead to further engine damage. - How do I reset a P1390 code?
You can reset it by using an OBD-II scanner after addressing any underlying issues. - What are common symptoms of a P1390 code?
Common symptoms include rough idling, poor acceleration, increased fuel consumption, and check engine light illumination. - Is it safe to replace a timing belt myself?
If you have mechanical experience, it can be done; otherwise, consider hiring a professional. - How long does it take to replace a timing belt?
The replacement process typically takes 4-8 hours depending on vehicle complexity. - What should I do if my check engine light comes back after repairs?
If it reappears, further diagnostics are needed as there may be additional underlying issues. - Are there any recalls related to P1390 codes?
You should check with your manufacturer for any recalls that might affect your vehicle’s performance.