EGR Valve - Functional Test

86MERCEDES01
TO: OUR MERCEDES-BENZ PASSENGER CAR DEALERS


DATE: March 1986 (supersedes MBNA 14/1a) REF.NO. MBNA 14/1b

SUBJECT: FUNCTIONAL TEST OF EXHAUST GAS RECIRCULATION (EGR) VALVE DIESEL ENGINES

NOTE: This issue revises the test procedure for EGR valves suspected of malfunction. Please discard your copy of MBNA 14/1a. Recent inspection of EGR valves returned under warranty has shown the majority to be fully functional. Therefore, it is absolutely necessary to follow the test specifications outlined here.

A - VALVE CLOSED B - VALVE OPEN:

With the engine off test the EGR valve as follows:

1. Apply 300 millibar vacuum with test pump. Pull vacuum hose off EGR valve connection. Valve seat must audibly snap back onto its seat.

2.. Apply 400 millibar vacuum with test pump. Vacuum loss after 60 seconds must not exceed 100 millibar.

3. Remove EGR valve. Apply vacuum with test pump to fully open the valve (equals 6 mm or 0.24 in. valve lift).
Nominal Value at Specified Valve Lift Valve Part Number

320 millibar 617 140 01 60 (blue)
520 millibar 617 140 02 60 (green)


If all three test steps are met, the valve is functional. The valve should be replaced if it does not meet one or more of the test steps.