EGR Function Testing - Diesel Volkswagen Golf Mk2

Checking Function

1. Engine oil temperature 50°C (122°F) minimum.
2. Start engine and let idle. EGR valve diaphragm rod is pulled toward vacuum hose connector. Diaphragm rod visible through opening on back side of diaphragm means exhaust gas is being supplied.
3. Slowly increase engine speed, when engine speed exceeds 1200 RPM, EGR is interrupted for 2 seconds. Diaphragm rod moves toward intake manifold for 2 seconds then moves back toward vacuum connection.
4. Continue to raise engine speed until part throttle switch closes. Diaphragm rod moves back toward intake manifold means EGR is interrupted.

If EGR does not work as described, go to Checking Activation .

Checking Activation

1. Switch ignition off.
2. Disconnect 2-pin harness connector from two-way valve for EGR.
3. Connect voltage tester using jumper cables from connector test kit to connector terminals.
4. Start engine and let idle. LED must light up.
5. Slowly increase engine speed. LED light most go out for 2 seconds and then light up again.
6. Continue to increase engine speed until EGR part throttle switch closes. LED must go out.

If control is OK, check EGR two-way valve or EGR valve.

If control is not OK, check engine coolant temperature sensor or check EGR part throttle switch.

If no malfunction is detected for engine temperature or for EGR part throttle switch, check wiring using Electrical Wiring Diagrams, Troubleshooting & Component locations, or replace automatic glow time control module, if necessary.

Diesel (ALH)

Testing the EGR system is done in function 04 (Basic setting). This procedure activates the EGR valve every 10 seconds to make it possible to read the extreme values for EGR (Mass Air Flow Sensor) in display field 3.

1. Connect scan tool and select control module for engine electronics with the "address word" 01. Engine must run at idle during this
2. Press buttons "0" and "4" for the function "initiate basic setting" and press "0" button to confirm input.
3. Press buttons "0" "0" and "3" for the "Display group number 3" and press "0" to confirm input.

Display field 2 must switch between EGR active and EGR not active every 10 seconds.

Display field 3 and 4 must move in the following control range

Note. If a constant value of 550 mg/H is displayed in display field 3, check the mass air flow sensor. See appropriate service information.

EGR not active

1. Specified value in display field 3: 400 to 580 mg/H
2. Specified value in display field 4: 0 to 5%

EGR active

1. Specified value in display field 3: 150 to 340 mg/H
2. Specified value in display field 4: 95 to 100%

Note. The readings in display field 3 are defendant on pressure and altitude. The displayed values refer to 0 m NN. If the measured values strongly differ due to altitude, check in display field 3 if there is a difference in specified value of at least 100 mg/H between the readings for EGR active and EGR not active.

If specifications are not obtained, see appropriate diagnostic information.

TEST 3

For EGR function testing, see appropriate article in ENGINE PERFORMANCE section of electronic information product.

See also:
• Checking Activation