LEMON Manuals: Even more car manuals for everyone
Home >> GMC >> 1991 >> Value Van 7.4 N >> Repair and Diagnosis >> Transmission >> Automatic Trans >> Diagnosis - A/T >> Diagnostic Flow Charts (Cars) >> Code 31, Park/Neutral Switch Circuit - 3.8L PFI (VIN L) >> Intermittent Test

Intermittent Test

Monitor a scan tool while moving related connectors and wiring harness. If failure is induced, scan data will change from LO to HI or HI to LO. Moving gear selector slowly through each gear position while monitoring PRNDL switch with scan tool may locate a faulty switch. This procedure may help isolate location of malfunction.

Fig 1: Code 31, Troubleshooting Diagram (3.8L PFI - VIN L)
G92D14848Courtesy of GENERAL MOTORS CORP.