Test Description

WARNING: This page is about a different car, the 2002 GMC Safari and 2002 Chevrolet Astro. However, it is still accessible from the selected car via links, so may be relevant.

The numbers below refer to the step numbers on the diagnostic table.

2) - Tests for the proper operation of the circuit in the low voltage range.
3) - Tests for the proper operation of the circuit in the high voltage range. If the fuse in the jumper opens when you perform this test, the signal circuit is shorted to ground.
4) - Tests for a short to voltage in the 5 volt reference circuit.

Fig 1: DTC B1398 Diagnosis (Steps 1-3)

Courtesy of GENERAL MOTORS CORP.

Fig 2: DTC B1398 Diagnosis (Steps 4-13)

Courtesy of GENERAL MOTORS CORP.