California

EGR System:

***UPDATED BY TSB NO. 9103001, JUNE 7, 199O
***UPDATED BY TSB NO. 9103001, JANUARY 3, 1991

EGR SYSTEM FUNCTION TEST

1. Begin this test with engine cold (coolant temperature below 15~C, 59~F).
2. Block front wheels.
2. Connect a tachometer to the engine.
3. Disconnect vacuum hose from EGR valve and connect a vacuum gauge to the hose.
2. Lift rear wheels and support off ground with stands.
4. Start engine and ensure that the vacuum gauge reads zero at all engine speeds.
5. Allow engine to warm up for a few minutes. Place transmission in gear.
6. Check that vacuum gauge reads zero at idle.
7. Rev engine to 3500 rpm and check that gauge now records the presence of vacuum.
8. Reconnect hose to EGR valve.
9. Rev engine to 3500 rpm and check that EGR valve diaphragm operates smoothly.

EGR TEMPERATURE SENSOR

If a malfunction in the EGR temperature sensor occurs, the ECM will set a code 32 or 34. For detailed EGR temperature sensor testing procedure, see COMPUTERIZED ENGINE CONTROLS. For a resistance test, proceed as follows:
1. Remove EGR temperature sensor from vehicle.
2. Immerse sensing end in a pan of oil.
3. Connect an ohmmeter across sensor electrical terminals and use an appropriate thermometer to measure oil temperature.
4. Heat oil and compare temperature and ohmmeter readings with chart.
5. If measured resistance deviates from the specified range, replace EGR temperature sensor.

Temperature ~C(~F) Approx. K Ohms

0 (32) 27.0
20 (68) 12.1
40 (109) 5.9
80 (176) 1.7
100 (212) 1.0

VACUUM SWITCHING VALVE (VSV)

1. Disconnect electrical connector and apply battery voltage to VSV electrical terminals. Air should flow freely through vacuum ports.
2. Disconnect electrical power. No air should pass through ports.
3. Replace VSV if it fails this test.

DUTY SOLENOID

1. Disconnect electrical connector and apply battery voltage to solenoid electrical terminals. Air should flow freely through vacuum ports.
2. Disconnect electrical power. No air should pass through ports.
3. Replace solenoid if it fails this test.