P1491 1999 Honda Civic Code - Exhaust Gas Recirculation Valve Insufficient Lift
Quick Answer
The Exhaust Gas Recirculation (EGR) system reduces Oxides of Nitrogen (NOx). Common causes include Faulty Exhaust Gas Recirculation (EGR) Valve, Exhaust Gas Recirculation Valve harness is open or shorted, Exhaust Gas Recirculation Valve circuit poor electrical connection. Severity is Moderate - service should be scheduled soon. The vehicle may still be drivable for short trips if it runs normally, but avoid hard driving and repair it soon.
- What it means
- P1491 1999 Honda Civic indicates Exhaust Gas Recirculation Valve Insufficient Lift.
- Common causes
- Common causes include Faulty Exhaust Gas Recirculation (EGR) Valve, Exhaust Gas Recirculation Valve harness is open or shorted, Exhaust Gas Recirculation Valve circuit poor electrical connection.
- Severity
- Moderate - service should be scheduled soon.
- Can I drive?
- The vehicle may still be drivable for short trips if it runs normally, but avoid hard driving and repair it soon.
Code P1491 1999 Honda Civic Description
The EGR system lowers peak combustion temperature by recirculating inactive exhaust gas into the air/fuel mixture, thus reducing NOx emissions.
The EGR valve position sensor is built into the EGR valve and detects the amount of valve lift. The command value for the target valve lift is previously stored in the Powertrain Control Module (PCM) so that exhaust gas recirculation can be optimized according to driving conditions.
Comparing this command value with the EGR valve position sensor output signal value, the PCM controls the EGR valve to make the amount of actual valve lift equal to the command value.
If the EGR valve position sensor output signal value differs greatly from the command value in the PCM memory for a set period of time, the EGR valve or the EGR valve position sensor is considered faulty and a DTC is stored.
What are the Possible Causes of the DTC P1491 1999 Honda Civic?
- Faulty Exhaust Gas Recirculation (EGR) Valve
- Exhaust Gas Recirculation Valve harness is open or shorted
- Exhaust Gas Recirculation Valve circuit poor electrical connection
- Exhaust Gas Recirculation Valve clogged
- Exhaust gas leaks
How to Fix the DTC P1491 1999 Honda Civic?
Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.
Code Tech Notes
What is the Cost to Diagnose the Code?
Labor: 1.0
To diagnose the P1491 1999 Honda Civic code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.
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Frequently Asked Questions about P1491 1999 Honda Civic Code
1. What are common symptoms of OBDII code P1491 on a 1999 Honda Civic related to the Exhaust Gas Recirculation (EGR) valve?
- Common symptoms include rough idling, decreased fuel efficiency, and the illumination of the check engine light.
2. What does the OBDII code P1491 indicating "Exhaust Gas Recirculation Valve Insufficient Lift" on a 1999 Honda Civic mean?
- This code indicates that the EGR valve is not opening enough to allow sufficient exhaust gas recirculation into the intake manifold.
3. What are the possible causes of OBDII code P1491 on a 1999 Honda Civic?
- The code P1491 can be triggered by a faulty EGR valve, a clogged EGR passage, a malfunctioning EGR solenoid, or electrical issues in the EGR system.
4. How can I diagnose the cause of OBDII code P1491 on my 1999 Honda Civic?
- Diagnosing the cause of P1491 involves testing the EGR valve, checking for clogs in the EGR passage, inspecting the EGR solenoid, and verifying the electrical connections in the EGR system.
5. What are the implications of ignoring OBDII code P1491 on a 1999 Honda Civic?
- Ignoring code P1491 can lead to poor engine performance, decreased fuel efficiency, and potential damage to other engine components over time.
6. Can I drive my 1999 Honda Civic with OBDII code P1491 triggered?
- It is not recommended to drive your vehicle with code P1491 triggered, as it can lead to engine performance issues and potential damage if left unresolved.
7. How can I repair OBDII code P1491 related to the Exhaust Gas Recirculation Valve on my 1999 Honda Civic?
- Repairing code P1491 may involve cleaning or replacing the EGR valve, clearing any obstructions in the EGR passage, testing or replacing the EGR solenoid, and ensuring proper electrical connections.
8. Is it possible to reset OBDII code P1491 on a 1999 Honda Civic without repairing the issue?
- It is possible to clear the code temporarily by resetting the ECU, but the code is likely to return if the underlying issue with the EGR system is not addressed.
9. How much does it typically cost to repair OBDII code P1491 on a 1999 Honda Civic at a mechanic or dealership?
- The cost of repairing code P1491 can vary depending on the specific issue, but it may range from $100 to $500 or more, including parts and labor.
10. Are there any preventive maintenance steps to avoid OBDII code P1491 on a 1999 Honda Civic in the future?
- Regularly servicing the EGR system, using high-quality fuel and performing routine engine maintenance can help prevent issues leading to code P1491 on your Honda Civic.
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