Pinpoint Test A: Loss Of Power

Exhaust System

Pinpoint Tests

PINPOINT TEST A: LOSS OF POWER

NOTE: The vehicle can have a lack/loss of power, odor, a noise or a "no start" concern. These concerns may be related to the exhaust system. Carry out the following test, if no DTCs were stored. This test is for diagnosing the source for these conditions. For diagnostic information, refer to Computers and Control Systems Information.

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A1 EXHAUST SYSTEM INSPECTION


- Inspect the exhaust system for damage or deterioration. Look for cracks, punctures, leaks, loose connections, dents or unusual bending.
- Is the exhaust system OK?

Yes
GO to A2.

No
REPAIR or INSTALL new exhaust components if damaged or deteriorated. TEST the system for normal operation.

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A2 EXHAUST SYSTEM FROZEN


- Inspect the exhaust system for frozen condensation.
- Park the vehicle inside to thaw.
- Is the restriction gone?

Yes
Exhaust system is OK.

No
GO to A3.

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A3 MANUAL REGENERATION PROCEDURE


NOTE: Do not install shop exhaust with vacuum to the vehicle tailpipe. The vacuum at the shop exhaust will alter the back pressure readings.

- Position the vehicle on the ground with the exhaust system exit free from obstructions and with adequate ventilation.
- Make sure the vehicle has at least one-fourth tank of fuel.
- Carry out the manual regeneration procedure. Refer to Computers and Control Systems Information.
- After regeneration is completed, gradually increase the engine speed to 1,800-2,000 rpm with the transmission in NEUTRAL.
- Is the restriction gone?

Yes
Exhaust system is OK.

No
GO to A4.

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A4 BACK PRESSURE TEST


- Position the vehicle on a hoist. Refer to Vehicle Jacking and Lifting.
- Remove the tail pipe. Refer to Tailpipe - 6.4L Diesel Tailpipe.
- Start the engine and gradually increase the engine speed to 1,800-2,000 rpm with the transmission in NEUTRAL.
- Is the restriction gone?

Yes
Install a new tail pipe.

No
GO to A5.

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A5 BACK PRESSURE TEST


- Remove the Diesel Particulate Filter (DPF). Refer to Diesel Particulate Filter - 6.4L Diesel Service and Repair.
- Start the engine and gradually increase the engine speed to 1,800-2,000 rpm with the transmission in NEUTRAL.
- Is the restriction gone?

Yes
INSTALL a new DPF.

No
GO to A6.

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A6 BACK PRESSURE TEST


- Remove the Oxidation Catalytic Converter (OC). Refer to Oxidation Catalytic Converter (OC) - 6.4L Diesel Oxidation Catalytic Converter (OC).
- Start the engine and gradually increase the engine speed to 1,800-2,000 rpm with transmission in NEUTRAL.
- Is the restriction gone?

Yes
INSTALL a new OC.

No
No indications of a restriction have been detected. CONDUCT a diagnosis on other suspect systems. CLEAR the DTCs.

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