P1491 Possible Causes
- Faulty Exhaust Gas Recirculation 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
First diagnose P1491 code
Check the "Possible Causes" listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded terminals.
Cost of diagnosing the P1491 code
Labor: 1.0The cost of diagnosing the P1491 code is 1.0 hour of labor. The auto repair labor rates vary widely across the country, and even within the same city. Most auto repairs shops charge between $75 and $150 per hour.
P1491 Possible Symptoms
- Engine Light ON (or Service Engine Soon Warning Light)
P1491 MeaningThe exhaust gas recirculation (EGR) system reduces oxides of nitrogen (NOx). NOx is generated by high combustion temperatures.
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.
P1491 More InformationNeed more information on how to fix the P1491 code?
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P1491 Information for specific makes
- P1491 ACURA Exhaust Gas Recirculation Valve Insufficient Lift
- P1491 AUDI EVAP Canister Purge Regulator Valve 2 Open Circuit
- P1491 CHRYSLER Radiator Fan Relay Circuit Condition
- P1491 DODGE Radiator Fan Relay Circuit Condition
- P1491 HONDA Exhaust Gas Recirculation Valve Insufficient Lift
- P1491 INFINITI Vacuum Cut Valve Bypass Valve
- P1491 ISUZU Exhaust Gas Recirculation Valve Insufficient Lift
- P1491 JEEP Radiator Fan Relay Circuit Condition
- P1491 MERCEDES-BENZ A/C System Pressure Too High
- P1491 NISSAN Vacuum Cut Valve Bypass Valve
- P1491 NISSAN SENTRA Vacuum Cut Valve Bypass Valve
- P1491 SAAB Evaporative Emission Pressure Sensor / Fuel Tank Level Sensor In Fuel Tank - Range / Performance Problem / Malfunction
- P1491 SUBARU PCV Function Problem
- P1491 VOLKSWAGEN EVAP Canister Purge Regulator Valve 2 Open Circuit