Emission Control System
Evaporative Emission Controls (cont'd)
(From page 11-137)
Warm up the engine to normal operating temperature (cooling
fan comes on). (From page 11-137)
Is there battery voltage ?
Inspect GRIM wire for an open
between ECU (A20) and the
connector. If wire is OK. substitute a
known-good ECU and recheck. If
symptom/incication goes away,
replace the orignal ECU.
Check for vacuum at #6 vacuum hose after starting the engine:
Is there manifold vacuum?
Disconnect the 6P connector.
Is there manifold vacuum?
Reconnect the hose. Inspect for a short to body
ground in GRN wire between ECU (A20) and the connector.
If wire is OK, substitute aknown-good ECU and recheck. If
symptom/indication goes away,
replace the original ECU.
Remove fuel filler cap.
(To page 11-139) Inspect vacuum hose
routing.
If OK, replace purge
cut-off solenoid valve. Repair open in BLK/
YEL wire between No. 2 fuse and the 6P con-
nector.ProCarManuals.com
Emission Control System
Evaporative Emission Controls
(cont'd)
Two-Way Valve Test 1. Remove the fuel filler cap.
2. Remove vapor line from the fuel tank and connect to T-fitting from vacuum gauge and vacuum pump
as shown.
VACUUM/PRESSURE GAUGE
0-4 in. Hg
07JAZ–001000A
VACUUM PUMP/
GAUGE
A973X–041–XXXXX
T—FITTING
3. Apply vacuum slowly and continuously while watching the gauge.
Vacuum should stabilize momentarily at 5 to 1 5
mmHg (0.2 to 0.6 in. Hg).
If vacuum stabilizes (valve opens) below 5 mmHg
(0.2 in. Hg) or above 15 mmHg (0.6 in. Hg), in-
stall new valve and retest.
4. Move vacuum pump hose from vacuum to pressure fitting, and move vacuum gauge hose from vacuum
to pressure side as shown.
PRESSURE SIDE
5. Slowly pressurize the vapor line while watching the
gauge.
Pressure should stabilize at 10 to 35 mmHg (0.4 to
1.4 in.
Hg).
If pressure momentarily stabilizes (valve opens)
at 10 to 35 mmHg (0.4 to 1.4 in. Hg), the valve
is OK.
If pressure stabilizes below 10 mmHg (0.4 in. Hg) or above 35 mmHg (1.4 in. Hg), install a
new valve and retest.ProCarManuals.com
