Engine Controls - System & Component Testing: Diagnosis Volkswagen EuroVan T4 рестайлинг

CONNECTING VAG TEST BOX

VISUAL INSPECTION

Perform a comprehensive visual inspection of underhood components. Check ground connections located on intake manifold, ground cable between engine and vehicle body and that battery cables are clean and tight. See ENGINE PERFORMANCE wiring diagrams in SYSTEM WIRING DIAGRAMS article in ELECTRICAL.

Check vacuum hoses for breakage and blockage. Check electrical wiring and harness connectors for damage and corrosion. Repair as necessary. Ensure all engine systems not related to ECM are operating properly.

Check for any Technical Service Bulletins (TSBs) that may apply. DO NOT proceed with testing unless all engine problems not related to ECM have been repaired.

OUTPUT DIAGNOSTIC TEST MODE

Output Diagnostic Test Mode is used when using Scan Tools VAG 1551/1552 or VAS 5051/5052, always continue with output diagnostic test mode until last component in output diagnostic test mode test sequence has been checked. If you are not using Scan Tools VAG 1551/1552 or VAS 5051/5052 follow scan tool manufacturer's instructions.

When Output Diagnostic Test Mode is performed on most engines ,Output Diagnostic Test Mode activates each component for 60 seconds, or until right arrow button is pushed to activate next component. Output Diagnostic Test Mode automatically terminates after 10 minutes.

When using scan tool in Output Diagnostic Test Mode to activate engine and emission components, components are checked either acoustically or by touch unless specified differently in component sequence list. Some components may be barely audible, check component by touch or use mechanics stethoscope if necessary.

OUTPUT DIAGNOSTIC TEST MODE WORK SEQUENCE

1. Connect scan tool. See «DATA LINK CONNECTOR»(ref-160798-S03646741422004030100000) .
2. Turn ignition on, engine off. Check ECM for DTCs, following scan tool manufacture's instructions to perform Output Diagnostic Test Mode.
3. If DTC(s) are present, see appropriate SELF DIAGNOSTICS article. If no DTC(s) are present check suspect component using Output Diagnostic Test Mode (if Output Diagnostic Test Mode is available for the suspect component).
4. If Output Diagnostic Test Mode is not available for the suspect component proceed with SYSTEM & COMPONENT TESTING.

TEST DRIVE RELEARN PROCEDURE

Note. When voltage supply to ECM is interrupted or codes have been cleared, ECM loses all "learned" and/or "basic" values. Serious driveability problems may occur depending on vehicle mileage. A relearn procedure must be performed.

1. If ECM was disconnected during diagnostic procedure or codes have been cleared, go to next step. If ECM was not disconnected during diagnostic procedure and no codes are present. Perform a test drive. Recheck for codes (no relearn procedure is necessary).
2. Turn ignition off. Remove test equipment. Reconnect ECM connector. Reconnect all remaining (disconnected) electrical connectors/components. Go to next step. NOTE: Throttle Valve Control Module (J338) adapts to ECM (J220) automatically if ignition is switched on for 10 seconds or more without operating accelerator pedal or starter and ECM recognizes a need for adaptation. No notification that adaptation was successful will be given when this happens.
3. Turn ignition on for a minimum of 10 seconds. Turn ignition off. Perform idle check, see «IDLE CHECK»(ref-160798-S24833712702004030100000) . Perform a long road test. Coolant temperature needs to be greater than 176°F (80°C). Idle, partial throttle, full throttle and overdrive, all must be attained several times. During test drive, apply full throttle until engine speed exceeds 3500 RPM. Read readiness code. Generate readiness code if necessary. See «READINESS CODE»(ref-160798-S16836341442004030100000) .

IAT Sensor Range & Circuit Testing: EuroVan 2.8L (Engine Code AXK)

Note. Engine must be cold before performing test procedure.

Note. On EuroVan 2.8L (engine code AXK), IAT sensor is located inside MAF sensor.

1. Verify battery voltage is a minimum of 11.5 volts and all fuses are okay. Repair as necessary. Connect Scan Tool. See «DATA LINK CONNECTOR»(ref-160798-S03646741422004030100000). Go to next step.
2. Turn ignition on. Using scan tool, check IAT sensor temperature value. If IAT sensor temperature value deviates greatly from underhood ambient temperature, go to step 4. If IAT sensor temperature value is approximately the same as underhood ambient temperature, go to next step. NOTE: Next test step tests IAT sensor through its full range.
3. Remove intake hose from MAF/IAT sensor and Throttle Control Module. Using a chilling agent, cool IAT sensor see scheme 29 Using scan tool, observe IAT sensor temperature value. Temperature value should steadily decrease. If IAT sensor temperature value did not steadily decrease, replace faulty MAF/IAT sensor. After repairs, erase DTC memory. Verify repair. Test is complete.
4. If IAT sensor temperature value is extremely low - approximately -50°F (-46°C) - possible cause is open circuit or short to positive. Go to next step. If IAT sensor temperature value is extremely high - approximately 285°F (141°C) - possible cause is short to ground. Go to step 6.
5. Disconnect MAF/IAT sensor connector. Using a jumper wire, bridge IAT sensor harness connector terminals No. 1 and 3. see scheme 28 Using scan tool, observe IAT sensor temperature value. If IAT sensor temperature value is approximately -50°F (-46°C), turn ignition off. Go to step 7. If IAT sensor temperature value is approximately 285°F (141°C), turn ignition off. Replace faulty MAF/IAT sensor. After repairs, erase DTC memory. Verify repair. Test is complete.
6. Disconnect MAF/IAT sensor connector. Using scan tool, observe IAT sensor temperature value. If after disconnecting MAF/IAT sensor connector, temperature value is approximately -50°F (-46°C), turn ignition off. Replace faulty MAF/IAT sensor. After repairs, erase DTC memory. Verify repair. Test is complete. If after disconnecting MAF/IAT sensor connector, temperature value is approximately 285°F (141°C), turn ignition off. Go to next step.
7. Disconnect ECM harness connector. Connect Test Box (VAG 1598/31) to ECM harness connector. See «CONNECTING VAG TEST BOX»(ref-160798-S19411562162004030100000). Disconnect MAF/IAT sensor 5-pin connector. Using DVOM, measure resistance between IAT sensor harness connector terminal No. 1 and test box socket No. 26. see scheme 28 Record resistance reading. Using DVOM, measure resistance between IAT sensor harness connector terminal No. 3 and test box socket No. 27. Record resistance reading. Resistance should be a maximum of 1.5 ohms for each reading. Go to next step.
8. Check IAT sensor harness connector terminal No. 1 for short circuit to battery positive and ground. Check IAT sensor harness connector terminal No. 3 for short circuit to battery positive and ground. Also verify IAT sensor harness connector circuits are not shorted to each other. Repair wiring harness as necessary. If wiring and IAT sensor are okay, replace faulty ECM. See ENGINE CONTROL MODULE under REMOVAL, OVERHAUL & INSTALLATION article. After repairs, erase DTC memory. Verify repair. Test is complete. Perform ECM relearn procedure. See «TEST DRIVE RELEARN PROCEDURE»(ref-160798-S02926260952004030100000).

IAT Sensor (G42) Testing: EuroVan 2.8L (Engine Code AES)

1. Turn ignition off. Disconnect IAT sensor connector. see scheme 6
2. Using DVOM, measure resistance of IAT sensor. Measure resistance between terminals No. 1 and 2 of IAT sensor. For IAT sensor specifications, see «IAT SENSOR (G42) RESISTANCE»(ref-160798-S09579471852004030100000) table.
3. If IAT sensor test is okay, go to «IAT SENSOR RANGE & CIRCUIT TESTING: EUROVAN (ENGINE CODE AES)»(ref-160798-S02227177082004030100000), (IAT sensor wiring needs to be tested). If resistance is not as specified, replace IAT sensor. After repairs, erase DTC memory. Verify repair. Test is complete. Perform ECM relearn procedure. See «TEST DRIVE RELEARN PROCEDURE»(ref-160798-S02926260952004030100000).

IAT Sensor Range & Circuit Testing: EuroVan (Engine Code AES)

Note. Engine must be cold before performing test procedure.

1. Verify battery voltage is a minimum of 11.5 volts and all fuses are okay. Repair as necessary. Connect Scan Tool. See «DATA LINK CONNECTOR»(ref-160798-S03646741422004030100000). Go to next step.
2. Turn ignition on. Using scan tool, check IAT sensor temperature value. If IAT sensor temperature value deviates greatly from underhood ambient temperature, go to step 4. If IAT sensor temperature value is approximately the same as underhood ambient temperature, go to next step. NOTE: Next test step tests IAT sensor through its full range.
3. For IAT sensor location (Scheme 1) Using a chilling agent, cool IAT sensor. Using scan tool, observe IAT sensor temperature value. Temperature value should steadily decrease. If IAT sensor temperature value did not steadily decrease, replace faulty IAT sensor. After repairs, erase DTC memory. Verify repair. Test is complete.
4. Disconnect ECM harness connector. Connect Test Box (VAG 1598/18) to ECM harness connector. See «CONNECTING VAG TEST BOX»(ref-160798-S19411562162004030100000). Disconnect IAT sensor 2-pin connector. Using DVOM, measure resistance between IAT sensor harness connector terminal No. 1 and test box socket No. 36. (Scheme 2) Record resistance reading. Using DVOM, measure resistance between IAT sensor harness connector terminal No. 2 and test box socket No. 33. Record resistance reading. Resistance should be a maximum of 1.5 ohms for each reading. Go to next step.
5. Check IAT sensor harness connector terminal No. 1 for short circuit to battery positive and ground. Check IAT sensor harness connector terminal No. 2 for short circuit to battery positive. Also verify IAT sensor harness connector circuits are not shorted to each other. Repair wiring harness as necessary. If wiring and IAT sensor are okay, replace faulty ECM. See ENGINE CONTROL MODULE under REMOVAL, OVERHAUL & INSTALLATION. After repairs, erase DTC memory. Verify repair. Test is complete. Perform ECM relearn procedure. See «TEST DRIVE RELEARN PROCEDURE»(ref-160798-S02926260952004030100000).

Scheme 1

Scheme 2

Fuel Injector Leak Test

1. Ensure fuel system pressure is within specification before performing this test. Remove fuel rail, complete with fuel injectors, from engine. DO NOT disconnect fuel supply or return lines. Using scan tool, energize fuel pump.
2. With fuel pump running, visually inspect fuel injector for leaks. Maximum allowable leakage is 1-2 drops of fuel per injector per minute. If fuel injector leaks more than 2 drops of fuel per minute, replace leaking fuel injector. Always replace fuel injector "O" rings.

Fuel Injector Resistance Test

Turn ignition off. Disconnect fuel injector electrical connector. Using a DVOM, measure resistance between fuel injector terminals. (Scheme 3)and FUEL INJECTOR RESISTANCE table. If resistance is not as specified, replace fuel injector.

FUEL INJECTOR RESISTANCE

Scheme 3

Fuel Injector Quantity Test (2.8L Engine AXK)

Note. Fuel injector quantity test procedure for 2.8L, engine code AES, is not available from manufacturer.

1. Remove fuel rail, complete with fuel injectors, from engine. DO NOT disconnect fuel supply or return lines. Place fuel injector being tested into a graduated container. Run fuel pump using output Diagnostic Test Mode (DTM). See «OUTPUT DIAGNOSTIC TEST MODE»(ref-160798-S05597661062004030100000) . Connect one terminal of fuel injector to battery positive terminal.
2. Connect other terminal of fuel injector to ground for exactly 30 seconds. Check fuel injector quantity. See «FUEL INJECTOR INJECTION QUANTITY»(ref-160798-S12899625162004030100000) table. If fuel quantity is more than or less than specification, replace faulty fuel injector.

FUEL INJECTOR INJECTION QUANTITY