Note On INTERMITTENTS

Manipulate related PCM and BCM wiring in each gear range while looking for a change in ED31 or BD41 display values to check for intermittent open or short to ground. Also check terminals for good contact at PCM, BCM and PRNDD21 switch. If good contact exists and Code B127 continues to set, replace PRNDD21 switch.

Fig 1: Code B127, Schematic, Gear Selector Switch Ckt

Courtesy of GENERAL MOTORS CORP.

Fig 2: Code B127, Flow Chart, Gear Selector Switch Ckt (1 of 3)

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Fig 3: Code B127, Flow Chart, Gear Selector Switch Ckt (2 of 3)

Courtesy of GENERAL MOTORS CORP.

Fig 4: Code B127, Flow Chart, Gear Selector Switch Ckt (3 of 3)

Courtesy of GENERAL MOTORS CORP.