| Subject: | naccurate EVAP Vent Valve and Fuel Tank Pressure Sensor Parameters on Tech 2 Versions 26.007 and Lower |
| Models: | 2007 Chevrolet Colorado |
| with 2.9L Engine (VIN 9 - RPO LLV) |
| or 3.7L Engine (VIN E - RPO LLR) |
The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
Condition/Concern:
When using Tech 2 version 26.007 or lower to perform EVAP system diagnosis, some technicians may notice the following Tech 2 Issues:
| • | The Fuel Tank Pressure Sensor Inches of H20 parameter is inaccurate. The Fuel Tank Pressure Sensor will read +5.9" of H20 when there is no pressure or vacuum in the EVAP system. When the EVAP system is pulled into a vacuum using the purge/seal
test on the Tech 2, the parameter will only decrease to +3.75 instead of reading negative numbers.
|
| • | The EVAP Vent Solenoid Command reads backwards. When the EVAP Vent Solenoid is commanded on, it reads Venting instead of Not Venting. When the EVAP Vent Solenoid is commanded off, it reads Not Venting instead of Venting.
|
Recommendation/Instructions:
If either of these concerns are encountered, do not replace the PCM. These concerns are the result of a concern with Tech 2 versions 26.007 and lower. If either of these concerns are encountered, update the Tech 2 to software version 26.008 or higher
and continue diagnosing the EVAP system.
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.
