S2018000007 Rev.

STAR ONLINE PUBLICATION
Case Number: S2018000007 REV. B
Release Date: 2/22/2021
Symptom/Vehicle Issue: Diagnostic Trouble Code (DTC) P0299 – Turbocharger
Underboost Additional Diagnostics
Discussion: When diagnosing a vehicle that has set DTC P0299, it is always
important to closely follow the normal published diagnostics for the DTC. In addition to
performing the steps outlined in the diagnostic flow chart, please also refer to the
additional diagnostic steps listed below to ensure a proper repair.
Diagnosis:
1. Remove, and inspect the engine air filter. Ensure that the air filter is clean, and not
restricted.
2. Inspect the bottom of the air filter to see if it utilizes glue strips to separate the
pleats. Newer design OEM replacement air filters, and some aftermarket filters
utilize glue strips to separate the pleats. Please see (Figure 1). There have been
reports that filters using this design can potentially cause this DTC. If the air filter
installed on the vehicle utilizes these glue strips, swap it with one that is not
equipped with them, and retest.
This document does not authorize warranty repairs. This communication documents a record of past experiences. STAR Online does
not provide any conclusions about what is wrong with the vehicle. Rather, it captures all previous cases known that appear to be
similar or related to the vehicle symptom / condition. You are the expert, and you are responsible for deciding on the appropriate
course of action.
Contact STAR Center, or your Technical Assistance Center Via TechCONNECT or eCONTACT ticket if no
solution is found
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1.
2.
Glue Strips
No Glue Strips
3. Ensure that the Charge Air Cooler (CAC) system is properly pressure tested per
the steps outlined in Service Library Service Information Section 09 – Engine, 6.7L
Diesel > Turbocharger System > Diagnosis and Testing – Leaks. While performing
the CAC leak testing, pay close attention to the CAC boot connected to the turbo
outlet for leaks caused by the wire harness rubbing through the boot. Please see
(Figure 2).
This document does not authorize warranty repairs. This communication documents a record of past experiences. STAR Online does
not provide any conclusions about what is wrong with the vehicle. Rather, it captures all previous cases known that appear to be
similar or related to the vehicle symptom / condition. You are the expert, and you are responsible for deciding on the appropriate
course of action.
Contact STAR Center, or your Technical Assistance Center Via TechCONNECT or eCONTACT ticket if no
solution is found
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STAR ONLINE PUBLICATION
4. If the boot is found damaged, replace as necessary, and retest the CAC system for
any additional leaks. Repair as necessary.
5. Remove the EGR Crossover tube from the EGR valve, and inspect the EGR inlet to
see if there are signs that the valve internal seat has begun to rotate. Please see
(Figure 3). The EGR internal shaft should be completely visible when looking into
the crossover tube inlet.
1.
Healthy part 2. EGR with rotated seat
This document does not authorize warranty repairs. This communication documents a record of past experiences. STAR Online does
not provide any conclusions about what is wrong with the vehicle. Rather, it captures all previous cases known that appear to be
similar or related to the vehicle symptom / condition. You are the expert, and you are responsible for deciding on the appropriate
course of action.
Contact STAR Center, or your Technical Assistance Center Via TechCONNECT or eCONTACT ticket if no
solution is found
FCA US LLC
Version 4.2 02/06/2017
STAR ONLINE PUBLICATION
6. Thoroughly inspect the EGR valve end cap for signs of leaks (Figure 4). If found to
be leaking, replace the EGR valve.
7. Inspect the DOC/DPF for signs of being face plugged, or for any other exhaust
system restrictions. Refer to the Aftertreatment Inspection Guidelines located in
Service Library Service Information Section 29 – Non DTC Diagnostics > Drivability
Diesel, 6.7L > Diagnosis, and Testing > Aftertreatment Inspection Guidelines. If the
DPF is face plugged, it will most likely need to be replaced. Before installing the
new DOC/DPF, please be sure proper diagnosis to the fuel, air intake, EGR, and
turbo systems have been performed and any defect repaired.
8. Using wiTECH, perform the “Turbo Hysteresis” test located in the PCM “Misc
Functions”. If the test fails, the turbo will have to be replaced.
9. Ensure that the PCM is at the latest available calibration.
This document does not authorize warranty repairs. This communication documents a record of past experiences. STAR Online does
not provide any conclusions about what is wrong with the vehicle. Rather, it captures all previous cases known that appear to be
similar or related to the vehicle symptom / condition. You are the expert, and you are responsible for deciding on the appropriate
course of action.
Contact STAR Center, or your Technical Assistance Center Via TechCONNECT or eCONTACT ticket if no
solution is found
FCA US LLC
Version 4.2 02/06/2017