P1491 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 Valve, Exhaust Gas Recirculation Valve harness is open or shorted, Exhaust Gas Recirculation Valve circuit poor electrical connection. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
- What it means
- P1491 indicates Exhaust Gas Recirculation Valve Insufficient Lift.
- Common causes
- Common causes include Faulty Exhaust Gas Recirculation Valve, Exhaust Gas Recirculation Valve harness is open or shorted, Exhaust Gas Recirculation Valve circuit poor electrical connection.
- Severity
- High - diagnose this code as soon as possible.
- Can I drive?
- Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
Code P1491 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?
- 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
How to Fix the DTC P1491?
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.
What is the Cost to Diagnose the Code?
Labor: 1.0
To diagnose the P1491 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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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 RAM — Radiator Fan Relay Circuit Condition
- 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
Frequently Asked Questions about P1491 Code
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