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Forum > Failed Smog Test > Question

How To Complete a VW Beetle Drive Cycle?

After replacing the battery in my Beetle, I failed the smog test. I was told to drive so that the EMS would reset. What are the driving specifics to reset it? The tech mentioned something about emission monitors??
Answer:

We understand your Volkswagen Beetle is having difficulty getting certain emission monitors to complete (become Ready). First off we should mention, at the time of this posting, the EVAP monitor is the one monitor allowed to be incomplete and your car still pass the smog check. So... if after you perform the drive cycle, you still have the EVAP monitor showing as incomplete, no need to worry, it can pass the smog check. Visit a local smog station and obtain the inspection. Your VW can pass the test.

Here's what happened when you replaced your VW Beetle's battery, it caused the OBD II monitors to erase, requiring a drive cycle to be completed in order to make the monitors READY or COMPLETE again. Follow the VW Beetle drive cycle below. The required monitors should become ready to pass the smog inspection simply by driving your car for 200-300 miles and over the course of a few days. Due to individual driving habits/patterns, sometimes the drive cycle parameters are not met with ordinary driving, and following the VW Beetle drive cycle is necessary.

Take extra caution when performing drive cycles on public roadways, obeying all traffic laws. Conduct the drive cycle at your own risk. You may also seek repair assistance from a VW dealership. They will be able to complete the drive cycle using manufacturer specific scan tools. If after performing the drive cycle twice your Beetle is still unable to pass the smog check because its monitors (or monitor) are incomplete, please seek assistance from a smog check repair center or VW dealership.

How To Complete VW Beetle Drive Cycle

The VW OBD-II drive cycle is an eight-step process. An explanation of each step is provided below. Total drive cycle time is 12 minutes.

NOTE: Do not leave the key on prior to the cold start or the oxygen sensor (O2S) heater monitor may not run.

Step 1: Cold Start — The ECM determines the presence of a cold start by comparing the engine coolant temperature to the ambient air temperature during startup. The engine is considered cold when:
• Engine coolant temperature is below 122°F.
• Engine coolant and intake air temperatures are within 11°F of each other at startup. During this period, the O2S heater, misfire, AIR, fuel system, and EVAP monitors run.

Step 2: Idle 2 1/2 Minutes — Turn the air conditioning (A/C) and headlights on to help the misfire monitor—the additional electrical loads help even out combustion pulses. During this period, the O2S heater, AIR, EVAP, misfire, and possibly fuel system (if operating in closed loop) monitors run.

Step 3: Accelerate — Prior to accelerating, turn off the A/C and headlights (if you had them on during step 2). Open the throttle halfway until you reach 55 mph. During acceleration, the misfire, fuel system, and EVAP monitors run.

Step 4: Steady State Cruise 3 Minutes — During this portion of the cycle, the O2S, AIR, EGR, EVAP, misfire, and fuel system monitors run.

Step 5: Decelerate — Gradually coast down to 20 mph without applying the brakes. Also, on manual transmission vehicles, remain in high gear and do not press the clutch. During this period, the EGR, EVAP, and fuel system monitors run.

Step 6: Accelerate—Apply ¾ throttle until reaching 60 MPH. During acceleration, the misfire, fuel system, and EVAP monitors run.

Step 7: Steady State Cruise 5 Minutes — During this period, the CAT, O2S, AIR, EGR, EVAP, misfire, and fuel system monitors run.

Step 8: Decelerate — Gradually coast down to 0 mph without applying the brakes. Also, on manual transmission vehicles, remain in high gear and do not press the clutch. During this portion of the Drive Cycle, the EGR, EVAP, and fuel system monitors run.

NOTE: If the CAT is marginal and the battery was disconnected prior to the drive cycle, it may take up to five separate drive cycles in order to determine the state of the catalytic converter.


posted by SmogTips Support

 

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