Troubleshooting Flowchart Inspection of Evaporative Emission
Contents
1. Troubleshooting Flowchart PURGE CONTROL Inspection of Evaporative DIAPHRAGM VALVE Emission Controls Disconnect vacuum hose from the purge control diaphragm valve on the charcoal canister and connect a vacuum gauge to the hose VACUUM PUMP GAUGE A973X 041 XXXXKX Start the engine and allow it to idle NOTE Engine coolant tempera ture must be below 70 C 158 F YES NO BLK YEL GRN Measure voltage between BLK YEL terminal and GRN ter minal ves Inspect vacuum hose Is there battery voltage routing If OK replace purge cut off solenoid valve NO Measure voltage between BLK YEL terminal and body ground To page 11 138 To page 11 138 cont d 11 137 Emission Control System Evaporative Emission Controls cont d From page 11 137 From page 11 137 Is there battery voltage NO YES Repair open in BLK YEL wire between No 2 fuse and the 6P con nector Warm up the engine to normal operating temperature cooling fan comes on Inspect GRIM wire for an open between ECU A20 and the connector lf 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 NO Is there manifold vacuum Disconnect the 6P connector YES Inspect vacuum hose l NO Is there manifold vacuum routing If OK repl2. ace purge cut off solenoid valve YES Inspect for a short to body ground in GRN wire between ECU A20 and the connector f wire is OK substitute a known good ECU and recheck If symptomi indication goes away replace the original ECU Reconnect the hose Remove fuel filler cap To page 11 139 11 138 From page 11 138 Connect a vacuum gauge to can ister purge air hose Start the engine and raise speed to 3 500 rpm NO Does vacuum appear on gauge within 1 minute YES See two way valve test to com plete Evaporative emission control are OK PURGE HOSE VACUUM PRESSURE GAUGE 0 4 in Hg 07JAZ 001000A TEZ i NT G r Q S P VA PURGE AIR HOSE Connect a vacuum gauge to the canister purge hose and raise the engine speed to 3 500 rpm Inspect the purge hose and throttle body port for pinch or blockage Does vacuum appear on the gauge YES Replace the canister cont d 11 139
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