Test H: Step 18

18) Attempt to Eliminate Code 41: Engines With MAP Sensor Turn key off. Install breakout box and reconnect ECA and HEGO sensor. Ensure MAP sensor vacuum hose is disconnected and plugged. Start and run engine at 2000 RPM for 2 minutes. Allow engine to return to idle. Apply 10-14 in. Hg to MAP sensor. Perform KOER Self-Test. If Code 41 is still present, remove breakout box. Reconnect ECA and MAP sensor vacuum line. If engine still runs rough, go to TEST S, step 2). If not, replace ECA and repeat QUICK TEST.

If Code 41 is not present, remove breakout box and reconnect ECA and MAP sensor vacuum hose. HEGO input circuit is okay. On sequential PFI engines, fuel delivery is okay, fault is in an area common to all areas. Service as necessary. On all other engines return to step 1) of this test.

NOTE: There is a break in the step numbering sequence at this point, skipping from step 18) to step 20). Break is due to previous chart references to these testing procedures. No test procedures have been omitted.