Fuel Trims Reading Lean or Engine Oil Leak - keywords 06 07 5.3 5.3L 6.0 6.0L P0171 P0174 block core dipstick DTC engine freeze galley H02S idle indicator leak lean level LH6 LS2 02 oil plug rough SES

This PI Supercedes To Include LS2 6.0L Engine. Please Discard PIP4038.

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

The customer concern may be rough running, a SES light, lean codes P0171/P0174, or an engine oil leak.

Complete the current SI diagnostics for any trouble codes or symptoms found.

If a vehicle has come to dealer with rough running, a SES light, lean codes P0171/P0174, or an engine oil leak, inspect for a missing or loose oil indicator tube plug.

The 5.3 and 6.0 V-8 engines have a extra dipstick/oil level indicator hole located on the lower right side (passenger side) of the engine. On certain vehicle applications the oil level indicator hole on the right side of the block is not used. This hole is plugged with an engine oil gallery plug if it's not utilized. If the block plug is loose or missing, it can cause the lean condition or an engine oil leak. Use SI procedures for Engine Block Plug Installation to install the new oil level indicator plug.

GMSPO does have a parts listing for the Oil Indicator Tube Hole Plug, and the current part number plug (or equivalent) should be used for this repair.

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.