S2018000007 Rev.

STAR ONLINE PUBLICATION
Case Number: S2018000007
Release Date: 9/01/2020
Symptom/Vehicle Issue: (Revision A) 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 is
an OEM replacement. Several reports have been received from the field of some
aftermarket replacement air filters causing this DTC to set. These filters may look
very similar to filters available through Mopar. If the filter is an aftermarket filter,
swap the filter with the proper Mopar replacement, and retest the DTC.
2. 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 1).
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
3. If the boot is found damaged, replace as necessary, and retest the CAC system
for any additional leaks. Repair as necessary.
4. 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 2). 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
5. Thoroughly inspect the EGR valve end cap for signs of leaks (Figure 3). If found
to be leaking, replace the EGR valve.
6. 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