Lack of Power or Poor Performance During High Ambient Temperatures with RPO (C7N) 12,300 LB GVWR or (C4M) 9,900 LB GVWR – 2016-2020 Chevrolet Express & GMC Savana

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Bulletin No.: PIP5800 Published date: 04/7/2021 Preliminary Information PIP5800 Lack of Power or Poor Performance During High Ambient Temperatures with RPO (C7N) 12,300 LB GVWR or (C4M) 9,900 LB GVWR Models Brand: Chevrolet GMC Model: Express Savana Model Years: 2016 – 2020 2016 – 2020 VIN: from to All All All All Engine: 6.0L L96 LC8 6.0L L96 LC8 All All Transmissions: Involved Region or Country Condition North America Some customers may comment that the vehicle exhibits a lack of power when driving up grades or after the vehicle has been idling for long periods of time in high ambient temperatures (90 degrees or above). This condition is more noticeable when the vehicle is outfitted with heavy work equipment on the back such as work boxes or ambulance bodies. When the ambient temperature drops below 90 degrees you may notice that the condition is less noticeable or eliminated altogether. Cause This condition is caused by the high ambient temperatures 90 degrees effecting the intake air flow to the engine. When looking at GDS2 scan tool data you may also notice an increase in total knock retard and ignition timing being backed out (chart shown below). This can occur while the vehicle is underload or driving in a situation where they may be going up a grade and more throttle input is required. The ECM is adjusting to protect the engine from engine damaging spark knock which are normal under these conditions. Correction: This issue is currently under engineering investigation. Below is a list of items to inspect to ensure are installed correctly and not missing or damaged. If any one of these components is missing or damaged this could allow hot air into the intake duct causing the lack of power concern. Questions Yes No Is the hood seal installed? (1) Are both CRFM side baffles driver and passenger side installed correctly? (2) Are both grille seals installed correctly? (3) Is the hood latch seal installed correctly? (4) Is the radiator upper baffle installed correctly? (5) Is the lower baffle installed correctly? (6) Is the air box drain valve installed correctly? Is the air box end cover installed properly? Are all intake air ducts installed correctly and clamps tight? Is the PCV hose installed correctly? Is the air box attached to upper tie bar with correct fasteners and secure? Has the up fitter installed components in front of the grille, blocking fresh air flow to CRFM? If so, please list them. Has the up fitter modified anything to attach their components? (Baffles, fascia, hood seal or anything else) Are there any holes cut/drilled in any sheet metal near the AIS inlet? Are there any DTC current or in history? If so, please list them Are the vehicles maintained in-house or taken to dealerships? How long does the vehicle idle? What was the outside temperature when the condition occurred? Did the vehicle have any check engine lights or warning messages (What was the reason for service visit)? Inspection: with 100% accelerator pedal apply during acceleration does MAP nearly equal the Barometric Pressure value? If not, check induction system for restriction Ensure there are no exhaust restrictions. Refer to service information for exhaust inspection and back pressure check. Inspect the intake duct for any restrictions. As information comes and/or a fix is released this PI will be updated. Warranty Information Labor Operation Description Labor Time 4087968 Lack of Power Vehicle Inspection 1.5 Hr. *This is a unique Labor Operation for Bulletin use only. Version History Version 1 Modified 04/07/2021 – Created on.  
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