Restricted Exhaust. GMC Truck GMC P42 Commercial Chassis 1999

For 1990-2009 cars only

Makes 🢒 GMC_Truck 🢒 1999 🢒 GMC P42 Commercial Chassis 🢒 Engine 🢒 Engine Controls - 4.3L 🢒 Restricted Exhaust

Restricted Exhaust Gasoline Engine

Step	Action	Value(s)	Yes	No
1	Check the exhaust tubing for kinks. Is the exhaust tubing kinked?	--	Go to Step 2	Go to Step 3
2	Repair the kinks in the exhaust system or replace the exhaust tubing. Is the exhaust system restricted?	--	Go to Step 3	System OK
3	Check for restrictions within the muffler. Refer to Restricted Exhaust System Check in Engine Controls. Are there any restrictions within the muffler?	--	Go to Step 4	Go to Step 5
4	Remove the muffler and examine it. If the muffler is damaged and cannot be repaired, replace the muffler. Is the exhaust system restricted?	--	Go to Step 5	System OK
5	Inspect the end of the tailpipe for any obstructions. Is the exhaust system restricted?	--	Go to Step 6	System OK
6	Remove the obstruction from the end of the tailpipe. If the end of the tailpipe is crimped, straighten the outlet. Is the exhaust system restricted?	--	Go to Step 7	System OK
7	Inspect the catalytic converter for restrictions that may have occurred as a result of engine malfunction. Refer to Restricted Exhaust System Check in Engine Controls. Is the catalytic converter restricted?	--	Go to Step 8	System OK
8	If the catalytic converter is damaged and cannot be repaired, replace the catalytic converter. Is the exhaust system restricted?	--	--	System OK

Restricted Exhaust Diesel Engine

Step

Action

Value(s)

Yes

Check the exhaust tubing for kinks.

Is the exhaust tubing kinked?

Go to Step 2

Go to Step 3

Repair the kinks in the exhaust system or replace the exhaust tubing.

Is the exhaust system restricted?

Go to Step 3

System OK

Check for restrictions within the muffler. Refer to Restricted Exhaust System Check in Engine Controls.

Are there any restrictions within the muffler?

Go to Step 4

Go to Step 5

Remove the muffler and examine it. If the muffler is damaged and cannot be repaired, replace the muffler.

Is the exhaust system restricted?

Go to Step 5

System OK

Inspect the end of the tailpipe for any obstructions.

Is the exhaust system restricted?

Go to Step 6

System OK

Remove the obstruction from the end of the tailpipe. If the end of the tailpipe is crimped, straighten the outlet.

Is the exhaust system restricted?

Go to Step 7

System OK

Inspect the catalytic converter for restrictions that may have occurred as a result of engine malfunction. Refer to Restricted Exhaust System Check in Engine Controls.

Is the catalytic converter restricted?

Go to Step 8

•	Occasional higher load operation should prevent the catalytic converter from being restricted.

•	Repeated full throttle accelerations may correct an existing condition.

•	Correct the engine malfunction.

Is the exhaust system restricted?

System OK