Diagnostic Aids

The 5-volt reference 1 circuit provides 5 volts to the following sensors:

• The manifold absolute pressure (MAP) sensor
• The fuel tank pressure (FTP) sensor
• The air conditioning (A/C) refrigerant pressure sensor
• The accelerator pedal position (APP) sensor 2
• The engine oil pressure (EOP) sensor
• The camshaft position (CMP) sensor

The 5-volt reference 2 circuit provides 5 volts to the following sensors:

• The APP sensor 1
• The throttle position (TP) sensor 1 and 2
• The crankshaft position (CKP) sensor
• The brake booster vacuum sensor

It may be possible to locate the fault by disconnecting one component at a time from the affected 5-volt reference circuit while viewing the 5-Volt Reference circuit status parameter on the scan tool. The scan tool parameter will change from Fault to OK when the source of the fault is disconnected. If all 5-volt reference components have been disconnected and a fault is still indicated, the fault may exist in the wiring harness.