P0489 OBD-II Trouble Code: Exhaust Gas Recirculation “A” Control Circuit Low

P0489 Code Definition

The P0489 code is a generic powertrain code related to auxiliary emissions control. If this code is stored, it is stated that the exhaust gas recirculation (EGR) “A” control circuit is reporting a low voltage flow.

Codes related to the P0489 include:

• P0405: Exhaust Gas Recirculation Sensor "A" Circuit Low
• P0406: Exhaust Gas Recirculation Sensor "A" Circuit High
• P0409: Exhaust Gas Recirculation Sensor "A" Circuit
• P0487: Exhaust Gas Recirculation Throttle Position Control Circuit
• P0488: Exhaust Gas Recirc Throttle Position Control Range/Perf
• P0490: Exhaust Gas Recirculation Control Circuit High
• P2413: Exhaust Gas Recirculation System Performance
  

What the P0489 code means

When a P0489 code is stored, it means that the engine control module (ECM) has detected a fault with an electrical component of the EGR system. The EGR system works to prevent the release of harmful emissions into the environment. To maintain cylinder head pressure, the EGR system is operated through the ECM, which opens or closes the EGR valve depending on the vehicle’s speed, temperature, and load.

The ECM has a preset degree of allowed change in the exhaust manifold. If the proper exhaust flow is not detected when the EGR valve is activated, a P0849 code can be stored. Depending on the make and model of your vehicle, an EGR position sensor may be used to monitor the EGR valve while the ECM determines the desired EGR flow based on how far open the valve is at the time. Some automakers measure manifold air pressure and exhaust feedback with a Delta Pressure Feedback EGR (DPFE) sensor.

What causes the P0489 code?

Several problems may cause a P0489 code including:

• Damaged, defective, or corroded wiring or connectors
• Possible short to ground
• Possible short to battery voltage
• Clogged EGR passages
• Clogged DPFE sensor passages
• Damaged or defective EGR system
• Damaged or defective EGR valve
• Damaged or defective EGR valve gasket
• Damaged or defective EGR control solenoid
• Damaged or defective EGR line
• Clogged MAP/MAF sensor
• Damaged or broken vacuum line/hose

What are the symptoms of the P0489 code?

Symptoms of a P0489 code may include:

• Warning or check engine light may illuminate
• Engine may run rough or idle choppy
• Decrease in overall vehicle fuel efficiency
• Drop in vehicle power
• Vehicle may hesitate to start or may not start at all
• The vehicle exhaust may be a darker black color
• The vehicle may not show any symptoms at all aside from the stored code

How does a mechanic diagnose the P0489 code?

A mechanic may use several methods to diagnose a P0489 trouble code, including:

• Utilize an OBD-II scanner to check for a stored P0489 trouble code

• Visually inspect all wiring and electrical connectors and harnesses for damages or defects

• Visually inspect all vacuum hoses, lines, and connectors for damage or leaks

• Determine how the EGR valve system is controlled (by ECM or vacuum)

• Monitor EGR function and compare with manufacturer recommendations

• Determine if the EGR valve is sticking

• Use a handheld vacuum pump to observe EGR operation to determine if the valve opens

• If vehicle does not stall when valve opens, check for clogged EGR passages

• If the engine stalls, check if the EGR control solenoid is working

• Test EGR control solenoid connector for a voltage and ground signal

• Test for a voltage signal between the ECM and EGR electrical connector

• Check for damaged, loose, or burnt wiring at the EGR valve and control solenoids or EGR and DPFE sensor

Common mistakes when diagnosing the P0489 code

The EGR valve is an expensive component to replace, and often when the P0489 code appears, many will be quick to replace it versus fully diagnosing the issue, which could simply be damaged wiring or a blown gasket.

How serious is the P0489 code?

Because a vehicle’s safe driving operation should not be impacted due to faults that store a P0489 code, but the vehicle can emit more harmful emissions, this code is considered a potentially serious code. When this code appears it is recommended to immediately take your vehicle to your local service center or mechanic for repair and diagnosis.

What repairs can fix the P0489 code?

Several repairs can fix a P0489 trouble code and include:

• Repair or replace any damaged or loose wiring, connectors, and harnesses
• Repair or replace any damaged or broken and leaking vacuum hoses and lines
• Repair or replace damaged or defective EGR control solenoid
• Carbon clean clogged EGR passages
• Clear all codes, test-drive the vehicle, and rescan to see if any codes reappear
• Replace the damaged or defective EGR valve

Need help with a P0489 code?

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