B4 Check The ISP-R Circuit For A Short To Ground

Key in OFF position.
Ignition Switch connector disconnected.

Measure the resistance between:

( + ) PCM Connector, Harness Side	( - ) Vehicle Battery
ISP-R - Pin B42	Negative terminal

Is the resistance greater than 10K ohms?
- Yes: CHECK the ignition switch for a short to ground.
  If the ignition switch is OK and DTC P2531 is present, GO to B5 .
  
  If the ignition switch is OK and DTC P2533 is present, GO to B9 .
- No: REPAIR the circuit.
  CLEAR the DTCs. REPEAT the self-test.