Tech Tip: Collisions Lead to Toyota EVAP Issues

Tech Tip: Collisions Lead to Toyota EVAP Issues

The Malfunction Indicator Light (MIL) is on in a 2004 Toyota Corolla, and codes P0441, P0442 and P0446 are set. It was determined that the vehicle was hit in the left front. Verify that the Vacuum Switching Valve (VSV) for the pressure sensor (located on the canister) operates correctly. This is a normally ....

CUSTOMER CONCERN:
The Malfunction Indicator Light (MIL) is on in a 2004 Toyota Corolla, and codes P0441, P0442 and P0446 are set. It was determined that the vehicle was hit in the left front.

Tests/Procedures:
1. Verify that the Vacuum Switching Valve (VSV) for the pressure sensor (located on the canister) operates correctly. This is a normally closed (NC) valve. When energized, it should open. When de-energized, an internal spring should close the valve. Also check the fuel filler neck according to Toyota TSB #EG051-06.

2. Verify that the canister closed valve (located on the air filter housing) closes and does not stick closed when operated. This is a normally open (NO) valve. When it is grounded, it closes and it should never stick closed.

3. If both solenoids operate correctly and are not sticking, inspect for restriction in the Evaporative Emission (EVAP) lines that could affect how the canister vents after a leak test is performed.

4. Verify that the purge VSV is connected to manifold vacuum on one side and the other port goes to the hose with the Green service port installed. If the purge VSV and the canister closed valve hoses are swapped, the codes will set.

Potential Causes: Defective VSV for the EVAP pressure sensor, fuel filler neck, fuel cap, defective canister closed valve, evaporative charcoal canister, restricted EVAP vacuum line(s) or misrouted vacuum hoses.

Confirmed Fix: Replaced the evaporative canister.

Tech Tips: If possible, use a scan tool to turn these two solenoids on and off. This is a good way to test the operation of the internal drivers inside the Engine Control Module (ECM) and the wiring harness. Refer to Toyota TSBs #EG005-01 and #EG013-03 for additional information on the EVAP system operation.

CUSTOMER CONCERN:
A 2004 Toyota Corolla idles rough and the oxygen sensors are reading low voltage all the time. Could they be faulty? A P0301, P0302, P0303, P0304 and P0171 code were displayed. This vehicle also was in a substantial accident and a number of parts were replaced.

Tests/Procedures:
1. If the engine is running poor and the oxygen sensors are reading a low voltage, add an external fuel supply to the engine. Check to see if it runs better and if the oxygen sensors climb in voltage.

2. Check the airflow meter grams per second at idle. 2.5-4.0 is normal.

3. Check the vehicle for a vacuum leak. Check for any hoses that may have been left off when the Corolla was being repaired. Check the hoses at the evaporative purge solenoid and the canister closed solenoid.

4. Run the vehicle on an external fuel supply until it runs smooth. Recheck the grams per second.

5. Inspect for a cracked intake manifold and/or a torn intake air boot. On a wide open throttle acceleration, check to see if the calculated load
reading goes to 85% or more. If not, the airflow meter may be faulty.

Potential Causes: Vacuum leak, Airflow meter or Fuel pressure/quality.

Confirmed Fix: The hoses were swapped at the purge solenoid and the canister closed valve.

Tech Tips: The vehicle did run better with added fuel. The grams per second were very low from the airflow meter. This vehicle was in an accident and came from a body shop. If the intake has a crack, there would be low flow through the airflow meter at idle due to the vacuum leak.

Courtesy of IDENTIFIX.

For additional tech tips, visit www.identifix.com.

You May Also Like

Gravity Releases Universal EV Charging ‘Trees’

The ‘trees’ require no utility upgrades and are capable of providing 200 miles of range in either 13 minutes (200kW) or 5 minutes (500kW).

Gravity has released a new universal on-street mounting and cable system, dubbed “DEAP Trees,” for its 200kW and 500kW Distributed Energy Access Points (DEAPs). Gravity said it is striving to develop a network of on-street DEAP charging more expansive than Tesla’s current Supercharger network.

Gravity’s engineers, in collaboration with design firm Rangr Studio, took on the challenge of solving frictions in curbside charging today. Each Gravity universal DEAP Tree has a hinged swing arm holding a cable that pivots down when charging begins, allowing it to reach the port of every make and model. When charging is completed, the arm raises automatically and the EV connector latches back onto the pole and out of sight.

Randy Breaux, Group President, GPC North America, Talks to AMN Drivetime

At NAPA, “Breaux Knows” business relationships, ABCs to avoid, and serving the automotive professional.

Is Training For The Sake Of Training Always Worth It?

Technology changes every day. Are you keeping your techs in top shape?

Understanding Customer Clunking And Clicking Complaints

Can Your Techs Diagnose and Repair Modern Axle Complaints?

Comprehensive Guide to Serpentine Belt and Drive System Maintenance

Properly maintaining the entire drive system prevents premature belt wear and system failure, ensuring customer satisfaction and vehicle reliability.

Other Posts

How Modern Car Sensors Optimize Performance and Emissions

Learn how Standard ensures accuracy, speed, and durability in their sensors to maximize engine performance and efficiency.

Chassis Parts and Alignment Angles

Knowing why the adjustment is required is critical to performing the total alignment.

Top 10 Wheel Bearing Torque Tips

A torque wrench is an essential tool when it comes to installing wheel bearings.

Blink CEO to Present at Energy, Power & Renewables Conference

The event is scheduled for June 17 at 1:10 p.m. ET.