| Subject: | Diagnostic/Repair Information for Check Engine/SES Light On, DTC P0171 Set |
| Models: | 2006 Chevrolet Equinox |
| with 3.4L V6 Engine (VIN F - RPO LNJ) |
This bulletin is being issued to provide information for a Check Engine/Service Engine Soon (SES) light illuminated . Upon inspection, the technician may find that Diagnostic Trouble Code (DTC) P0171 has been stored.
This condition may be caused by one of the following:
| • | Fresh air inlet pipe for the PCV system may have become disconnected or unplugged from the rear rocker cover. See Note in Correction section below. |
| • | Air or vacuum leak in any PCV hoses or fittings. |
| • | Oil level gage (dipstick) missing the O-ring or not fully installed in tube. |
| • | Oil fill cap missing the O-ring or not fully installed in rocker cover. |
| • | Air or vacuum leak between the upper and lower intake manifolds. Using a torque wrench, verify that all fasteners are tightened to specification. |
| • | Air or vacuum leak between the lower intake manifold and the cylinder heads. Using a torque wrench, verify that all fasteners are tightened to specification. |
| • | Loose clamps or an air leak in the duct located between the Mass Air Flow (MAF) sensor and throttle body. |
| • | Verify that the throttle body mounting fasteners are tightened to specification. |
| • | Vacuum leak in the hose going to the power brake booster. |
| • | Small air leak in the exhaust system between the engine and the Oxygen (O2) sensors. This type of leak may or may not be loud enough to hear. A small opening may allow outside air to be drawn into the pipe by the suction created by the exhaust
flow moving past the opening inside the pipe. |
| • | Aftermarket "performance enhancers" (inserted into the air flow duct to create turbulence or higher air flow). |
| • | Aftermarket air filter (non-AC Delco) that drastically alters or changes the direction of the air flow. |
| | Important: A restricted (dirty) air filter will not cause this DTC.
|
| • | An inaccurate (skewed) reading of air flow by the MAF sensor. Using a Tech 2, compare the MAF sensor readings to that of a known good vehicle under the same operating conditions. |
Perform repairs as necessary based on your findings. In addition, please be advised that a new calibration is in TIS2WEB at this time.
Refer to SI for additional diagnostic information.
Important: If the fresh air inlet pipe is found to be disconnected from the rear rocker cover, reinstall it and verify it is secure by pulling lightly. If it pulls out easily, clean the pipe and area around the rocker cover opening
to remove any oily residue. Reinstall the pipe and, if necessary, apply a bead of RTV or an appropriate adhesive to secure it to the rocker cover grommet.
