Diagnostic Aids
WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2018 GMC Yukon XL, 2018 GMC Yukon, 2018 Chevrolet Tahoe, 2018 Chevrolet Suburban, and 2018 Cadillac Escalade ESV. However, it is still accessible from the selected car via links, so may be relevant.
The 5V reference 1 circuit provides 5 V to the following sensors:
- Air conditioning (A/C) refrigerant pressure sensor
- Camshaft position sensor
- Engine oil pressure sensor
- Fuel pressure sensor
- Fuel rail pressure sensor
- Fuel tank pressure sensor
- Multifunction intake air sensor
The 5V reference 2 circuit provides 5 V to the following sensors:
- Brake pedal position sensor
- Crankshaft position sensor
The 5V reference 3 circuit provides 5 V to the following sensors:
- Accelerator pedal position sensor 2
- Manifold absolute pressure sensor
The 5V reference 4 circuit provides 5 V to the following sensors:
- Accelerator pedal position sensor 1
- Throttle position sensor
Disconnecting one component at a time from the affected 5V reference circuit while observing the scan tool 5V Reference Circuit Status parameter may help locate the fault. The scan tool parameter will change from Malfunction to OK when the source of the fault is disconnected. If all 5V reference components have been disconnected and a fault is still indicated, the fault may exist in the wiring harness.