DSM.0008 Ver 1.0
FCCC MT-45 / MT 55 CNG Diagnostics Service Manual
February 15, 2022
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FCCC MT CNG
63
FCCC MT CNG
DSM.0008 Ver 1.0
FCCC MT-45 / MT 55 CNG Diagnostics Service Manual
February 24, 2022
P
RINTED AND
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OWNLOADED
C
OPIES ARE
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OT
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ONTROLLED
63
Step 3
Inspect induction system for;
• plugged air filter
• collapsed air filter
• damaged induction tubing
• loose or missing vacuum port
• loose or missing vacuum cap
Above listed damage found:
Repair or replace component(s).
Perform System Verification Procedure.
No damage found:
Proceed to Step 4.
Step 2
Inspect the ignition system and fuel injectors.
Loose or damaged connectors found:
Repair damage. Refer to harness and wire
repair procedure DSM.0036.
Perform System Verification Procedure.
Loose or damaged connectors not found:
Proceed to Step 3.
Step 1
Start and idle vehicle.
The vehicle exhibits a misfire condition:
Proceed to Step 2.
The vehicle does not exhibit a misfire condition:
Operate the vehicle under the conditions
when the fault code set.
If the fault code does not set, return the
vehicle to service.
Never probe an electrical connection with anything other than an appropriately
sized shaped test lead. Doing so may result in damage to components.
Engine Misfire Diagnostics
Step 4
Perform PSI Cylinder Power Balance Test.
Refer to OEM procedure.
Cylinder(s) failed:
Proceed to Step 5.
Cylinders(s) passed:
Proceed to Step 6.
Step 5
Install a fuel injector Noid test light on suspect cylinder(s).
Start, and idle the engine.
Does the light pulse comparable to the other injectors not exhibiting this condition?
Damaged parts located:
Replace the injector(s) as needed and
retest.
Perform System Verification Procedure
.
No damaged parts:
Repair the open or high resistance in the
injector driver circuit.
