Diesel Engine Extended Idle Smoking - keywords 6.6 black blue excessive fuel injector LBZ LLY smoke soot white

This PI Superceded To Include Current Model Year. Please discard PIP3722.

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

A dealer may encounter a customer concern of excessive smoke after a extended idle time. Extended idle time is a idle time of more than 20 to 30 minutes. After extended idling, a light blue smoke may be noticed from the tailpipe. The smoke may be seen during the idle period, or on acceleration after the idle period.

Complete the current SI diagnostics for Excessive Smoke (Gray or Blue), or any trouble codes found.

If normal diagnostics are inconclusive, compare the amount of smoke to a like vehicle after a extended idle. The catalytic converter will collect exhaust particulates during extended idle periods. When the catalytic converter heats up, the particulates are cleared, and may be seen as a light blue smoke.

If the smoke is comparable to a like vehicle, there are no other objectionable driveability symptoms, and the vehicle symptoms are as described in this PI, the extended idle smoke should be considered a characteristic of the vehicle.

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.