EVAP System Troubleshooting

1.Disconnect the vacuum hose (A) from the EVAP canister (B) and connect a vacuum gauge (C) to the hose.

 


2.Start the engine and let it idle.

NOTE: Engine coolant temperature must be below 65°C (149°F).

Is there vacuum?


YES - Inspect vacuum hose routing. If OK, replace the EVAP canister purge valve.n


NO - Go to 3.


3.Hold the engine at 3,000 rpm (min-1) with no load (in Park or neutral) until the radiator fan comes on, then raise the engine speed to 3,000 rpm (min-1).

Is there vacuum?


YES - Go to 4.


NO - Inspect vacuum hose routing. If OK, replace the EVAP canister purge valve.n


4.Turn the ignition switch OFF.

5.Reconnect the vacuum hose to the EVAP canister.

6.Remove the fuel fill cap.

7.Disconnect the purge air hose (A) from the EVAP canister and connect a vacuum pressure gauge 0-100 mmHg (0-4 in.Hg) (B) to EVAP canister (C).

 


8.Start the engine and raise speed to 3,000 rpm (min-1).

Does vacuum appear on gauge within 1 minute?


YES - See EVAP two way valve test to complete. Evaporative emission controls are OK.n


NO - Replace the EVAP canister.n

1.Inspect the No. 4 ACG (10A) fuse in the under-dash fuse/relay box.

Is fuse OK?


YES - Go to 2.


NO - Replace the fuse, and recheck.n


2.Disconnect the vacuum hose (A) from the EVAP canister (B) and connect a vacuum pump/gauge (C) to the hose.

 

3.Start the engine and let it idle.

NOTE: Engine coolant temperature must be below 65°C (149°F).

4.Quickly raise the engine speed to 3,000 rpm (min-1).

Is there vacuum?


YES - Go to 5.


NO - Go to 11.


5.Disconnect the EVAP canister purge valve 2P connector.

6.Quickly raise the engine speed to 3,000 rpm (min-1).

Is there vacuum?


YES - Inspect vacuum hose routing. If OK, replace the EVAP canister purge valve.n


NO - Go to 7.


7.Turn the ignition switch OFF.

8.Disconnect the negative cable from the battery.

9.Disconnect ECM/PCM connector B (24P).

10.Check for continuity between EVAP canister purge valve 2P connector terminal No. 2 and body ground.

 

Is there continuity?


YES - Repair short in the wire between the EVAP cansiter purge valve and the  ECM/ PCM (B21).n


NO - Substitute a known-good ECM/PCM and recheck. If the symptom/indication goes away, replace the original  ECM/ PCM.n


11.Start the engine. Hold the engine at 3,000 rpm (min-1) with no load (in Park or neutral) until the radiator fan comes on, then let it idle.

12.Check for vacuum at the vacuum hose after the starting the engine.

13.Quickly raise the engine speed to 3,000 rpm (min-1).

Is there vacuum?


YES - Go to 24.


NO - Go to 14.


14.Turn the ignition switch OFF.

15.Inspect the vacuum hose rooting.

Is the vacuum hose OK?


YES - Go to 16.


NO - Repair the vacuum hose.n


16.Disconnect the EVAP canister purge valve 2P connector.

17.Turn the ignition switch ON (II).

18.At the harness side, measure voltage between EVAP canister purge valve 2P connector terminals No. 1 and No. 2.

 

Is there any voltage?


YES - Replace the EVAP canister purge valve.n


NO - Go to 19.


19.At the harness side, measure voltage between EVAP canister purge valve 2P connector terminal No. 1 and body ground.

 

Is there battery voltage?


YES - Go to 20.


NO - Repair open in the wire between No. 4 ACG (10A) fuse in the under-dash fuse/relay box and the EVAP canister purge valve.n


20.Turn the ignition switch OFF.

21.Reconnect the EVAP canister purge valve 2P connector.

22.Turn the ignition switch ON (II).

23.Measure voltage between ECM/PCM connector terminal B21 and body ground.

 

Is there battery voltage?


YES - Substitute a known-good ECM/PCM and recheck. If the symptom/indication goes away, replace the original  ECM/ PCM.n


NO - Repair open in the wire between the EVAP canister purge valve and the  ECM/ PCM (B21).n


24.Reconnect the vacuum hose to the EVAP control canister.

25.Remove the fuel fill cap.

26.Disconnect the purge air hose (A) from the EVAP canister and connect a vacuum/pressure gauge 0-100 mm Hg (0-4 in. Hg) (B) to EVAP cainster (C).

 

27.Start the engine and raise speed to 3,000 rpm (min-1).

Does vacuum appear on gauge within 2 minute?


YES - When vacuum is appear, evaporative emission controls are OK. Check the EVAP two way valve test.n


NO - Replace the EVAP canister.n