Technical Service Bulletin (TSB)
Make Up Air (MUA) Valve Leak
REFERENCE:

TSB: 09-010-23 REV. A
GROUP 09 - Engine

VEHICLES
AFFECTED:

2023 (WS) Grand Wagoneer/Wagoneer
This bulletin applies to vehicles before **June 22, 2023 (MDH
0622XX)** equipped with the 3.0L I6 Twin Turbo Engine W/ESS (Sales
Code EFH).

Date:

June 14, 2023

REVISION: 09-010-23
MARKET APPLICABILITY:
HNA
HMEA
□SA

□IAP

□EE

□CH

CUSTOMER
SYMPTOM:

Customers may experience a Malfunction Indicator Lamp (MIL) illumination. Upon further investigation
the technician may find that the following Diagnostic Trouble Code (DTC) has been set:
• P2C90 - Crankcase Ventilation System - Hose 9A9 Disconnected.

CAUSE:

MUA check valve spring undersized (too short).

This bulletin supersedes Technical Service Bulletin (TSB) 09-010-23, date of issue March 16, 2023,
which should be removed from your files. All revisions are highlighted with **asterisks** and include
an updated buld date, RSU number, LOPs, parts table, Inspection Procedure and Repair Procedure
steps.
This Technical Service Bulletin (TSB) has also been released as a Rapid Service Update (RSU) **23168, date of issue June 14, 2023**. All applicable RSU VINs have been loaded. To verify this RSU
service action is applicable to the vehicle, use VIP or perform a VIN search in DealerCONNECT/
Service Library. All repairs are reimbursable within the provisions of warranty. This RSU will expire 18
months after the date of issue.
REPAIR SUMMARY:
This bulletin involves replacing the MUA check valve, or performing an inspection and possibly replacing the
PCV valve.
CLAIMS DATA:
Labor Operation No:

Labor Description

Skill Category

Labor Time

**25-01-17-9K

Perform Crankcase Ventilation System Test –
Inspection
(Inspection Only)
(0 - Introduction)

09 - Engine

0.6 Hrs.

25-01-17-9M

Perform Crankcase Ventilation System Test
Inspection, Replace
Make Up Air (MUA)
Valve, PCV Valve and
Repeat Test Inspections
(0 - Introduction)

09 - Engine

0.9 Hrs.

25-01-17-50

Second PCV Valve
Replacement and Additional Test Inspection
(0 - Introduction)

09 - Engine

0.3 Hrs.

09-010-23 REV. A

-2-

Labor Operation No:

Labor Description

Skill Category

Labor Time

25-01-17-51

Third PCV Valve
Replacement and Additional Test Inspections
(0 - Introduction)

09 - Engine

0.5 Hrs.

25-01-17-9L

Perform Crankcase Ventilation System Test
Inspection and Replace
Make Up Air (MUA)
Valve
(0 - Introduction)

09 - Engine

0.7 Hrs.**

Failure Code

ZZ

Service Action

Qty

Part No.

Description

**1 (AR)

68358481AD

Valve, PCV**

1 (AR)

68483328AC

Valve, Check

SPARE PARTS:
Notes
MUA

DIAGNOSIS:
Using a Scan Tool (wiTECH) with the appropriate Diagnostic Procedures available in DealerCONNECT/
Service Library, verify all related systems are functioning as designed. If DTCs or symptom conditions, other
than the ones listed above are present, record the issues on the repair order and repair as necessary
before proceeding further with this bulletin.
If a customer’s VIN is listed in VIP or your RSU VIN list, perform the Inspection Procedure. If any vehicle not
on the VIN list exhibits any of the symptom listed above in the customer symptom section, perform the
Inspection Procedure.
1. **Was the vehicle built before March 06, 2023?
• YES>>> Proceed to Step 2 of the Repair Procedure.
• NO>>> The vehicle was built after March 06, 2023. Proceed to Step 2.
2. Start the engine.
3. Ensure the transmission is in the park position.
NOTE: Engine coolant temperature must remain above 80 °C (176 °F) while performing this
Inspection Procedure.
4. Idle the engine until the engine coolant temperature reaches 80 °C (176 °F).
NOTE: The MAX A/C button is only available on the touchscreen.
5. Turn the Heating, Ventilation and Air Conditioning (HVAC) to MAX A/C (blower speed will default to
high).
6. Turn off engine and wait five minutes.

7.
8.
9.
10.

NOTE: If coolant temperature has dropped below 80 °C (176 °F), allow engine to idle until that
temperature has been achieved.
Restart engine and ensure engine settles to 1,200 RPM after start up. Verify engine coolant
temperature is 80 °C (176 °F) or above.
Once coolant temperature exceeds 80 °C (176 °F) and engine RPM at 1,200, apply the brake pedal and
shift the transmission into the drive position.
Hold the vehicle while in drive for 30 seconds.
Shift the vehicle back into the park position and turn the engine off.

-3-

09-010-23 REV. A

11. Repeat steps Step 4 through Step 6. Then proceed to Step 12.
12. Using wiTECH, check for DTC P2C90.
13. Was DTC P2C90 present?
• YES>>> Proceed to Step 1 of the Repair Procedure.
• NO>>> This bulletin has been completed. Use inspect LOP (25-01-17-9K) to close the active RSU.
Or use the proper Inspect With Additional Test LOPs (25-01-17-50 or 25-01-17-51) to close the
active RSU if a second or third test was performed.**
SPECIAL TOOLS/EQUIPMENT:
Description

Ref. No.

Notes

wiTECH or Equivalent

–

–

REPAIR PROCEDURE:
CAUTION! **Do not replace the PCV valve more than three times if DTC P2C90 persists. If the DTC is
still present after a third replacement and test, normal diagnosis should be performed.
1. Replace the PCV valve. Refer to the detailed service procedures listed in DealerCONNECT>Service
Library under: 25 - Emissions Control / Crankcase Ventilation / Valve, Positive Crankcase Ventilation
(PCV) / Removal and Installation. Use LOP (25-01-17-9M). Proceed to Step 3.**
2. Replace the MUA check valve. Refer to the detailed service procedures listed in
DealerCONNECT>Service Library under: 25 - Emissions Control / Crankcase Ventilation / Valve, Make
Up Air (MUA) / Removal and Installation. Proceed to Step 4.
NOTE: **Ensure the vehicles Low Fuel Warning Light is not on for the inspection test. In the
event the Low Fuel Warning Light in on, add three gallons fuel in the fuel tank.
3. Repeat Step 2 through Step 13 of the Inspection Procedure until DTC P2C90 is not present, performing
the test and replacement of the PCV valve no more than three times.**
4. Clear all DTCs that may have been set.
POLICY:
Reimbursable within the provisions of the warranty.
This bulletin is supplied as technical information only and is not an authorization for repair. No part of this publication may be reproduced, stored in a retrieval system, or
transmitted, in any form or by any means, electronic, mechanical, photocopying, or otherwise, without written permission of FCA US LLC.