Subject: | Additional Diagnostic For Yaw/Lat Sensor DTCs |
Models: | 2003-2006 Cadillac Escalade, Escalade ESV, Escalade EXT |
2003-2006 Chevrolet Avalanche, Suburban, Tahoe |
2003-2006 GMC Yukon, Yukon Denali, Yukon XL, Yukon Denali XL |
With RPO JL4 |
This PI is was updated to correct a connector number change. Please discard PIT3750.
The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
When performing normal diagnostics, it should be noted that the supply voltage at the yaw/lat sensor MUST be between 4.75v and 5.25v, as measured across ckts 2088 and 2087. The only way to verify the proper supply voltage is to use the Digital Multimeter J-39200 (Fluke 87) set to the Peak Min/Max feature (1 ms record). Backprobe the yaw/lat sensor connector terminals 1 and 6 and set the Multimeter to peak min/max feature (1 ms record) and drive vehicle and make sure supply voltage does not fall outside of the specified range.
If the supply voltage to the yaw/lat sensor does not stay within 4.75v and 5.25v, check ckt 2088 and 2087 for high resistance/opens, shorts to ground, or shorts to voltage.
Important: Reports of high resistance/opens in circuits 2088 or 2087 have been found between connectors C206 and C114 (or C102 for later models) behind the dash (Doc ID #1242519). To check this, perform a voltage drop on these circuits using the Digital Multimeter J-39200 (Fluke 87) set to the Peak Min/Max feature (1 ms record) and test drive vehicle. If excessive voltage drop is found (max .2v) repair as necessary.
Note: Be aware that excessive yaw sensor voltage fluctuation, due to erratic supply voltage, can set a false C0455.
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.