| Subject: | DTC Pertaining To 5 Volt Reference Concern |
| Models: | 2004-2006 Buick Rendezvous |
| 2005-2006 Buick LaCrosse/Allure |
| 2004-2006 Cadillac CTS, SRX |
The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
Condition/Concern:
When diagnosing trouble codes involving the following components:
| • | Mass Air Flow(MAF)/Intake Air Temperature (IAT) Sensor |
| • | Barometric Pressure (BARO) Sensor |
| • | Engine Oil Pressure (EOP) Sensor |
| • | Throttle Position (TP) Sensor |
| • | Accelerator Pedal Position (APP) Sensor |
| • | A/C Refrigerant Pressure Sensor |
| • | Fuel Tank Pressure (FTP) Sensor |
Recommendation/Instructions:
Be advised the LY7 and the LP1 engine control module is not equipped with a 5-volt reference diagnostic trouble code (DTC). The components listed above share the 5-volt reference A circuit. In most cases, if an open, shorted to ground, or shorted to
a voltage exists in the shared 5-volt reference A circuit, DTC P0102 MAF Sensor Circuit Low Voltage may be the only DTC to set. This is due to the MAF sensor circuit diagnostic being the first to run after the open, shorted to ground, or short to
voltage occurred. If there is a condition with the 5-volt reference circuit, make sure to test all the shared circuits and components.
Be sure to reference the Engine Data Sensors 5 Volt Reference(s) Bus schematic in eSI when diagnosing DTCs involving the listed components.
Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.
