2010 Honda CR-V Check Engine Light? How to Fix a Strut Issue

The Basics

The Check Engine Light (CEL), or Malfunction Indicator Lamp (MIL), is your vehicle's primary diagnostic warning system. It illuminates when the Engine Control Unit (ECU) detects a fault in the emissions, engine, or transmission control systems. The light can be solid or flashing, with a flashing light indicating a severe misfire requiring immediate attention to prevent catalytic converter damage. To diagnose the issue, you must read the stored Diagnostic Trouble Code (DTC) using an OBD-II scanner. Based on an analysis of 100 owner discussions, common codes triggering the CEL include P0420 (catalyst efficiency), P0442/P0457 (evaporative emissions leaks), P0661 (variable tumble control valve), and P1077 (variable induction control solenoid).

What Drivers Experience

Owners report a wide range of experiences when the CEL illuminates, often with no immediate change in drivability. Many note the light comes on intermittently, sometimes turning off after several drive cycles only to return later. Others experience it in conjunction with specific symptoms: a rough idle or loss of power with P0420 codes, a noticeable fuel smell with P0442/P0457 leak codes, or a lack of high-end power with codes like P0661 and P1077. A frequent point of confusion and frustration is the light appearing after unrelated work, such as suspension repairs involving struts or outer tie rod ends, leading owners to suspect incorrect reassembly or sensor damage.

What Causes It

The root cause is entirely dependent on the specific Diagnostic Trouble Code (DTC). Based on confirmed fixes from owner reports:

• P0420 (Catalyst Efficiency Below Threshold): Most commonly caused by a failing catalytic converter. However, it can also be triggered by exhaust leaks upstream of the converter, faulty oxygen sensors (particularly Bank 1 Sensor 2), or engine issues like misfires or oil consumption that have poisoned the catalyst.
• P0442 & P0457 (Evaporative Emission System Leaks): These small and large leak codes are frequently traced to a loose, damaged, or missing gas cap. Other culprits include cracked evap hoses, a faulty purge valve/solenoid, or a leaking fuel tank or filler neck.
• P0661 & P1077 (Intake Air System Control): These codes point to faults in the variable intake manifold systems. Typical failures include a stuck or failed control solenoid valve, a broken vacuum actuator diaphragm, or issues with the associated vacuum hoses and electrical connections.
• Non-Engine Work: In several discussions, the CEL appeared after suspension work. This is often coincidental but can be caused by accidentally disconnecting or damaging a wiring harness or sensor while working on struts, control arms, or tie rod ends.

Testing Procedures

Proper diagnosis requires a systematic approach to avoid replacing good parts.

1. Retrieve Codes: Use a reliable OBD-II scanner to pull all stored codes and freeze frame data. Note if codes are pending or confirmed.
2. Clear Codes & Monitor: For intermittent issues, clear the codes and drive the vehicle. Monitor via scanner to see which codes return and under what conditions (e.g., cold start, full throttle).
3. Code-Specific Diagnostics:
   • P0420: Use a scan tool to graph the pre-cat (Sensor 1) and post-cat (Sensor 2) oxygen sensor waveforms. A properly functioning catalytic converter will dampen the oscillations from Sensor 2. Similar patterns on both sensors indicate a failed cat. First, rule out exhaust leaks and engine mechanical issues.
   • P0442/P0457: Perform a smoke test on the evap system. This is the most definitive way to locate leaks in hoses, valves, the gas cap seal, or the fuel tank. Visually inspect all evap lines, especially around the fuel filler neck and charcoal canister.
   • P0661/P1077: Perform an actuator test on the control solenoid using a capable scan tool. Check for vacuum at the solenoid and actuator with a vacuum gauge. Inspect the vacuum hose for cracks and the electrical connector for corrosion or poor contact.
4. Visual Inspection: Always conduct a thorough visual inspection of the engine bay and undercarriage for disconnected wires, damaged sensors, or obvious leaks, especially if the CEL followed recent repair work.

What Works

Solutions are ranked by code frequency and cost-effectiveness.

1. Address Evap Leaks (P0442/P0457): The single most common fix is the simplest. Tighten or replace the gas cap. This resolved the issue in numerous reports. If the code persists, the next step is to inspect and replace cracked evap hoses or a faulty purge valve. A smoke test is highly recommended before replacing the charcoal canister or fuel tank.
2. Diagnose P0420 Thoroughly: Do not immediately replace the catalytic converter. First, ensure there are no engine misfires or exhaust leaks. Then, test/replace the downstream oxygen sensor (Bank 1 Sensor 2), as it is a frequent failure point and far less expensive than a catalyst.
3. Fix Intake Control Faults (P0661/P1077): The most common successful repair is replacing the failed control solenoid valve. Check the associated vacuum hose for leaks and the electrical connector for issues first, as these are minimal-cost fixes.
4. Investigate Recent Work: If the CEL appeared after suspension service, retrace your steps. Look for any unplugged connectors (e.g., for ABS wheel speed sensors) or pinched wires near the strut towers or steering rack.

Budget Planning

Costs vary dramatically based on the root cause and who does the work.

• DIY (Do-It-Yourself):
  • Gas Cap: $15 - $40.
  • Oxygen Sensor: $50 - $150 for the part.
  • Evap Purge Solenoid/Vacuum Hoses: $30 - $100.
  • Intake Control Solenoid: $80 - $200.
  • Tools: A basic OBD-II scanner costs $30-$100. A professional-grade scanner or smoke tester is a larger investment but pays for itself with accurate diagnosis.
• Professional Repair:
  • Diagnostic Fee: $100 - $150 is standard.
  • Evap System Repair (after diagnosis): $200 - $600 depending on part(s) replaced.
  • Oxygen Sensor Replacement: $200 - $350 total.
  • Catalytic Converter Replacement: $800 - $2,500+ (parts and labor), heavily dependent on the vehicle and whether an OEM or aftermarket part is used.
  • Intake Solenoid/Actuator Repair: $250 - $500 total.

Recommendation: Investing in a basic scanner and attempting simple fixes like the gas cap, visual hose inspections, and checking connectors is the most budget-friendly start. For complex diagnostics like a smoke test or oscilloscope reading of O2 sensors, a professional shop is often more efficient and cost-effective in the long run.

Prevention Guide

While some electronic failures are inevitable, you can minimize CEL events.

1. Secure the Gas Cap: Always tighten it until it clicks three times after refueling.
2. Address Small Problems Promptly: Fix minor engine issues like a slight misfire or vacuum leak immediately. Ignoring them can lead to catalyst damage (P0420) or other secondary faults.
3. Protect Wiring During Repairs: When performing suspension or other mechanical work, be mindful of nearby wiring harnesses and sensors. Use zip ties to secure wiring away from moving components.
4. Use Quality Fuel and Perform Regular Maintenance: Consistent use of Top Tier fuel and adhering to your vehicle's maintenance schedule (spark plugs, air filter) keeps the engine running efficiently and reduces the risk of emissions-related codes.
5. Periodic Visual Checks: During oil changes, quickly look for cracked, brittle, or disconnected vacuum and evap hoses, especially in older vehicles.

Source Summary: This analysis is based on 100 owner discussions from Reddit and automotive forums.