Vehicle: 2004 Volkswagen Beetle GLS 2.0L, L4, MFI, SOHC

Customer Concern: The check engine light is on, with trouble code P2187, too lean off idle bank 1.

Potential Causes:
– Defective Mass Air Flow (MAF) Sensor
– Leaking Engine Vacuum
– N80 Canister Purge Solenoid

Tests:

1. Check and verify that there are no vacuum leaks or ­un-metered air leaks.

2. Check the MAF sensor grams/second readings as ­follows:

  a. Idle (about 830 rpm) 3.5 grams/sec. or more (4 to 4.5 grams/sec. preferred).

  b. 2,500 rpm no load, 9 to 15 grams/sec. (11 to 12 grams/sec. preferred).

  c. Wide open throttle road (WOT) load (drive vehicle at 45 mph in third gear and perform a WOT acceleration, observe maximum indicated grams/sec. readings on the MAF); 90 or more grams/sec. preferred.

  d. A MAF that exhibits ­consistently lower than normal grams/sec. readings can cause a P0102 code to set.

3. Check for a leaking N80 Canister Control Valve. This can cause a vacuum leak and a lean idle condition.

Confirmed Fix: Replaced the MAF sensor.

Courtesy of Identifix’s “Five Fast Fixes.”