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Circuit Test D4

NOTE: Perform this test when Service Code 85 is displayed during QUICK TESTS or when directed here by other test procedures.
Fig 1: Canister Purge (CANP) Circuit
G54801
  1. Checking System Function. Enter OUTPUT STATE CHECK see OUTPUT STATE CHECK, under QUICK TEST DIAGNOSTIC AIDS. Use only DVOM, not diagnostic tester, for this step. Turn key off and wait 10 seconds. Set DVOM on 20-volt scale. Connect DVOM negative test lead to STO and positive test lead to positive battery terminal. Using jumper wire, connect STI circuit to SIGNAL RETURN at SELF-TEST connector. Perform KOEO SELF-TEST until end of Continuous Memory Codes (DVOM reads zero volts). Depress and release throttle. DVOM should change to a high voltage reading. If reading did not change, depress throttle to WOT and release. If STO voltage does not go high, go to CIRCUIT TEST D16 , step 1). Leave test equipment hooked up. If reading changed, remain in OUTPUT STATE CHECK and go to next step.
  2. Checking Solenoid Electrical Function. With KOEO, set DVOM on 20-volt scale. Disconnect CANP solenoid. Connect DVOM positive test lead to VPWR circuit and negative test lead to CANP output circuit on harness connector. While observing DVOM, depress and release throttle several times to cycle output on and off. If CANP circuit does not cycle on and off, remove jumper wire and go to step 6). If CANP circuit cycles, go to next step.
  3. Checking Solenoid For Vacuum Leaks. Turn key on. Leave CANP solenoid disconnected. Disconnect vacuum hose at canister purge solenoid from manifold vacuum side of engine. Apply 16 in. Hg vacuum to manifold vacuum side of CANP solenoid. If CANP solenoid does not hold vacuum for 20 seconds, replace it and repeat QUICK TEST. If fault is still present, service fuel evaporation canister. If CANP holds vacuum for 20 seconds, leave vacuum pump attached and go to next step.
  4. Checking Solenoid Mechanical Operation. While still in OUTPUT STATE CHECK, cycle CANP circuit off (no voltage). Reconnect CANP solenoid connector. Apply 16 in. Hg vacuum to CANP solenoid as in step 3). Depress and release throttle. If vacuum is released, check hose from solenoid to canister for leaks or cracks, if okay, remove jumper wire from STI and go to next step. If vacuum is not released, replace CANP solenoid and repeat QUICK TEST.
  5. Checking Vacuum Supply. Disconnect vacuum hose from canister purge solenoid on manifold vacuum (PVC) side. Start engine. If vacuum is present at vacuum hose, EEC system is okay. Check evaporative canister. If vacuum is not present at hose, check vacuum hose for proper routing, kinks, or blockage, If okay, check engine for cause of low vacuum.
  6. Measuring CANP Solenoid Resistance. Code 85 indicates a fault in the CANP solenoid circuit. Turn key off and wait 10 seconds. Set DVOM on 200-ohm scale. Disconnect CANP solenoid connector and measure solenoid resistance. If reading is between 40-90 ohms, go to next step. If reading is incorrect, replace CANP solenoid and repeat QUICK TEST.
  7. Checking Voltage of VPWR Circuit. With KOEO, and CANP solenoid disconnected, set DVOM on 20-volt scale. Measure voltage between VPWR circuit at CANP solenoid harness connector and battery negative terminal. If reading is 10.5 volts or greater, go to next step. If reading is less than 10.5 volts, repair open in circuit and repeat QUICK TEST.
  8. Checking Continuity of CANP Circuit. Turn key off and wait 10 seconds. Disconnect CANP solenoid and ECA 60-pin connector. Inspect connector for damaged pins, corrosion, or loose wires. Repair if necessary. Connect breakout box, leaving ECA disconnected. Set DVOM on 200-ohm scale. Measure resistance between test pin No. 31 and CANP harness connector. If reading is less than 5 ohms, go to next step. If reading is 5 ohms or more, repair open circuit and repeat QUICK TEST.
  9. Checking For Short to Ground. Turn key off and wait 10 seconds. Install breakout box, leaving ECA disconnected. Set DVOM on 200K-ohm scale and disconnect CANP solenoid. Measure resistance between test pin No. 31 and test pins No. 40, 46, and 60. If all readings are 10K ohms or more, go to next step. If any reading is less than 10K ohms, repair short to ground and repeat QUICK TEST.
  10. Checking For Short to Power. Turn key off and wait 10 seconds. Disconnect CANP solenoid. Install breakout box, leaving ECA disconnected. Set DVOM on 200K-ohm scale and disconnect CANP solenoid. Measure resistance between test pin No. 31 and test pins No. 37 and 57. If all reading are 10K ohms or more, remove breakout box. Replace ECA and repeat QUICK TEST. If any reading is less than 10K ohms, repair short to power and repeat QUICK TEST. If code is repeated, replace ECA and repeat QUICK TEST.
  11. Check If CANP Caused Codes 16 or 26. With key off, disconnect vacuum hose at canister purge solenoid on canister side. Start engine and allow to idle. If vacuum is present on canister side of canister purge solenoid, go to step 1), in this test. If vacuum is not present, and a Code 26 is displayed, check for vacuum leaks or lack of vacuum. If Code 16 is present, check for vacuum leaks at injector "O" rings, vacuum lines and fittings, or between air meter and throttle body. Service as necessary and rerun QUICK TEST.
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