FSB 284-048

Mack Trucks, Inc.
Greensboro, NC USA
Field Service Bulletin
Trucks
Date
Group
No.
Release
Page
2.2014
284
048
01
1(3)
Oil Pressure Sensor Jumper Harness
CHU, CXU, GU, LEU, MRU, TD
FSB 284-048, Oil Pressure Sensor Jumper Harness
(February 2014)
Some MACK vehicles with MP engines built between January 2004 and January 2013 may
experience a main oil gallery pressure sensor or piston cooling jet pressure sensor failure that
leads to oil contamination into the engine wire harness. A new anti-wicking jumper harness,
part number 22205127, is available. This jumper harness will stop oil from wicking back down
and possibly causing damage to the new sensor or cause later improper diagnostics. Oil
pressure sensor part number 21302639 is replaced with a new oil pressure sensor part
number 21634021. Follow the procedure below if wicking is observed. Part numbers are
stamped on the side of the sensors.
Note: It is not necessary to replace the entire engine harness for oil contamination.
If a sensor is being replaced for electrical faults and oil has NOT wicked into the harness,
REPLACE THE SENSOR ONLY.
If a sensor has failed AND is wicking oil into the engine harness, REPLACE THE SENSOR
AND INSTALL THE JUMPER HARNESS AS INSTRUCTED IN THIS BULLETIN.
If the engine harness is being replaced for other reasons and the sensor is part number
21302639 or older, REPLACE THE SENSOR ONLY. The new harness will NOT require the
jumper harness.
Note: Both sensors should be part number 21634021.
Required Parts
Jumper harness part number 22205127.
PV729-FSB284-048_M
USA62965
Mack Trucks, Inc.
Field Service Bulletin
Date
2.2014
Group
No.
Release
284
048
01
You must read and understand the precautions and guidelines in Service Information,
Function Group 30, "General Safety Practices, Electrical and Electronics" before
performing this procedure. If you are not properly trained and certified in this procedure,
ask your supervisor for training before you perform it.
Repair
1 Secure the vehicle for service by parking it on a flat level surface, applying the parking
brake, chocking the rear wheel, and placing the transmission in neutral.
2 Disconnect all cables from the negative (ground) battery terminals to prevent personal
injury from electrical shock and prevent damage to electrical components.
3 Raise hood or raise cab.
4 For cabover models, remove the charge air cooler (CAC) pipe from the engine
turbocharger outlet and CAC inlet. Remove the CAC temperature sensor from the pipe
and set the pipe aside.
5 Clip applicable cable ties and remove P-clamps securing the oil pressure sensor harness.
Disconnect the oil pressure sensor harness from the sensor.
6 Reverse the back shells on the jumper harness connectors before installing the jumper
harness. Connect the 90 degree end of the jumper harness to the oil pressure sensor and
the straight end to the harness. Install cable ties and P-clamps as necessary.
7 If oil has wicked to the engine control module connectors, clean the connectors thoroughly
with electronic cleaner and dry with compressed air.
8 If removed, install the CAC pipe. Tighten the V-band clamps to 7 ±1 Nm (62 ±9 in-lb).
Install the CAC temperature sensor.
9 Install all the previously removed cables to the negative (ground) battery terminals.
10 Start the engine and check for proper operation.
11 Close hood or lower cab.
12 Use Tech Tool to clear any diagnostic trouble codes (DTC).
Page
2(3)
Mack Trucks, Inc.
Field Service Bulletin
Date
2.2014
Group
No.
Release
284
048
01
Page
3(3)
Reimbursement
This repair may be eligible for reimbursement if a product failure was experienced within time and mileage limits of
the applicable Warranty coverage. Reimbursement is obtained via the normal claim handling process.
Claim Type (used only when uploading from the Dealer Bus. Sys.)
01
Labor Code
Primary Labor Code
2732F-01-80 — 0.3 hrs
Causal Part
21302639
Mack Trucks Inc. reserves the right to make any changes in design or to make additions to or
upon its products without incurring any obligations to install the same on vehicles previously
built.