EGR System Inspection

On other vehicles, the only way to accurately check the operation of the EGR system is to perform a systematic inspection of the entire system. The following inspection procedures are for a 95 5S-FE Camry:

• First, inspect the EGR modulator filter and, if necessary, remove and clean the filter with compressed air.

• "Tee" a vacuum gauge into the vacuum line between the EGR valve and VSV.

• Start the engine and confirm that it does not run rough at idle. Note: This verifies that the EGR valve is closed.

• Next, connect terminals TE1 to E1 at DLC 1.

• With coolant temperature cold (A/T: below 140' F, M/T: below 131' F) and engine at 2500 rpm, the vacuum gauge should indicate zero.

Note: This verifies that the VSV is inhibiting EGR flow during cold engine operations.

• Next, warm the engine to operating temperature and maintain 2500 rpm. The vacuum gauge should now indicate low vacuum (typically around 3")

Note: This verifies proper low vacuum signal to the EGR valve during light engine load conditions.

• Next, with engine speed at 2500 rpm, connect the R port of the EGR modulator directly to a manifold vacuum source. The vacuum gauge should now indicate high vacuum (typically around 13") and the engine should run rough.

Note: This verifies proper high signal vacuum to the EGR valve when R port vacuum overrides the backpressure modulator.

Disconnect terminals TE1 and El at DLC1 and reattach the EGR hoses to their original location.

If the problem is related to the EGR valve itself, make sure heavy carbon deposits are not keeping the valve unseated or causing it to stick when opening. Also, if EGR valve control is OK remove the valve and check the EGR exhaust and intake passages for restrictions. Heavy carbon deposits can be removed by using a special carbon scrapping tool.

This inspection example systematically confirms the integrity of the EGR valve, VSV, backpressure modulator, system hoses, and EGR passages. Once the suspect part/component is identified, it should be individually tested and then repaired or replaced as necessary. Because slight model to model variations exist between EGR systems, refer to the Repair Manual for specific EGR system inspection procedures.

When inspecting the EGR valve, look for common problems such as unseated or sticky valves and plugged exhaust/intake passages.

EGR Valve Inspection

Egr Valve Inspection
Do It Yourself Car Diagnosis

Do It Yourself Car Diagnosis

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