December 25, 2023

Acura CL (1998-2003) Running Rough? Engine Light?

Acura CL check engine light, stalling, runs rough After my Acura CL developed symptoms like an engine light, rough idle, and a long start, I knew what was needed.  If your model is from 1998-2003, you might have an issue with the Exhaust Gas Recirculation (EGR) valve. It plays a key role in reducing emissions and improving your vehicle’s efficiency. However, when it malfunctions, it can lead to various symptoms like the check engine light, rough idle, reduced fuel economy, engine vibrations, hesitation or stalling, long start time, and failed smog tests.  Be sure to check for Recalls.

Understanding the EGR Valve in Your Acura CL

The EGR valve plays a crucial role in reducing emissions by recirculating a portion of the exhaust gases back into the engine’s combustion chamber. This process lowers the combustion temperature, which in turn reduces the formation of harmful nitrogen oxides (NOx).

Common Symptoms of EGR Valve Problems

  • Check Engine Light: One of the first signs of an EGR valve problem is the illumination of the check engine light. This is often accompanied by specific OBD codes such as P0401 (EGR Flow Insufficient) and P1491 (EGR Valve Lift Insufficient Detected).  See the complete OBD code list.
  • Rough Idle: A malfunctioning EGR valve can cause your CL to idle roughly due to irregular air-fuel mixture.
  • Reduced Fuel Economy: It doesn’t get the same mileage, might be the EGR valve.
  • Engine Vibrations: You might feel unusual vibrations, especially at idle.
  • Hesitation or Stalling: The EGR valve can lead to hesitation during acceleration or even stalling.
  • Long Cranking Time: It might take longer for your engine to start if the EGR valve is not working properly.
  • Failure in Smog Tests: A faulty EGR can lead to increased emissions, causing your CL to fail emission tests.

Troubleshooting in Your Acura CL

  • Check Engine Light Codes: Use an OBD-II scanner. P0401 and P1491 are common, but other codes related to the EGR system can include P0402 (EGR Flow Excessive) and P0403 (EGR Circuit Malfunction).
  • Visual Inspection: Check the EGR valve for signs of damage or clogging.
  • Testing the Valve: You can test the EGR valve by applying vacuum to it and checking if the engine’s idle is affected.
  • Check the Vacuum Line: Ensure that the vacuum line to the EGR valve is intact and not leaking.
  • Inspect the EGR Ports: Sometimes, the ports in the EGR system can get clogged. Cleaning them can resolve the issue.

Other OBD Codes

  • P0400: EGR Flow Malfunction
  • P0402: Excessive EGR Flow
  • P0403: EGR Circuit Malfunction
  • P0404: EGR Circuit Range/Performance
  • P0405: EGR Sensor A Circuit Low
  • P0406: EGR Sensor A Circuit High

How to Replace the EGR Valve on Your Acura

  1. Locate the EGR Valve: It’s usually mounted on the engine block or cylinder head.
  2. Disconnect the Battery: Always start by disconnecting the battery.
  3. Remove the Old EGR Valve: Disconnect any electrical connections and vacuum lines, then unscrew the valve from its position.
  4. Install the New Valve: Position the new EGR valve and screw it in place. Reconnect any electrical connections and vacuum lines.
  5. Reconnect the Battery and Test: After installation, reconnect the battery and start your CL to ensure the issue is resolved.

Final Thoughts

Problems with the EGR valve in the Acura CL can lead to various issues like rough idling, engine vibrations, and increased emissions. Timely identification and resolution of these issues are crucial for maintaining your vehicle’s performance and compliance with emission standards. Remember, if you’re not comfortable performing these steps, always consult a professional mechanic.