Page 284
REPAIR INSTRUCTIONS, PART 1
VTG SYSTEM BENCH
PROCEDURES
VTG Control Valve Solenoid
Replacement
[214 QB]
A malfunctioning VTG control valve as indicated
by an active 4-5 FMI-7 fault code can sometimes
be caused by oil from the vehicle air system
entering the valve.
Additional troubleshooting information for a
4-5 fault code is outlined in the V-MAC
®
III
Service Manual, 8-211.
Oil in the control valve can result in blocked
pressure balance ports and a sticking solenoid
plunger shaft. If this condition is encountered,
replacement of the entire valve is not necessary.
A malfunctioning VTG control valve can be
repaired by replacing the solenoid with a solenoid
replacement kit available through the MACK
Parts System.
320
Figure 320 — VTG Control Valve
Using Figure 320 as a reference, replace the
solenoid as follows:
1. Remove the VTG control valve from the
engine.
2. Cap the air inlet port, outlet port and the
electrical connector.
3. Thoroughly clean the control valve external
surfaces, paying particular attention to the
surfaces around the solenoid-to-valve body
mating area where contaminants could enter
the valve when the solenoid is removed.
4. Open the jaws of a vise approximately
1-3/4″ (45 mm), and then place the control
valve front side down (air inlet port side) on
the open jaws so that the two press pin
holes clear the jaws.
On some of the earlier valves, the press pin holes
may be covered by the part number label on the
front side of the valve.
5-111.bk Page 284 Monday, July 10, 2006 2:26 PM
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