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Engine Controls - Tests W/codes: Diagnosis Volvo V90 I

Testing & Diagnostics ~24409 words

SELF-DIAGNOSTIC SYSTEM

Volvo S90 and V90 models use the Motronic 4.4 engine management system. System uses a single Electronic Control Module (ECM) to control fuel injection and ignition systems. This system is similar to the Motronic 4.4 system used on C70, S70, and V70 vehicles.

Signals from various sensors are monitored continuously. If certain signals are lost or become faulty, ECM will adopt fixed substitute values (limp-home mode) to enable vehicle to be driven for certain failures. Substitute values can be adopted for Engine Coolant Temperature (ECT) sensor signal, Throttle Position (TP) sensor signal, Mass Airflow (MAF) sensor signal, and oxygen sensor (HO2S) signal.

Note. To avoid confusion if there is an intermittent malfunction with Malfunction Indicator Light (MIL), carefully read following text.

ECM stores Diagnostic Trouble Codes (DTCs) differently in accordance with a predetermined pattern. An emission related fault must be present for a predetermined number of intervals before ECM permanently stores a DTC and illuminates Malfunction Indicator Light (MIL). If fault is cleared before a specified interval has passed, DTC is erased from memory. There are 3 main types of intervals

  1. Trip - All diagnostic functions have been performed.
  2. Running Cycle - Fuel trim (closed loop) has been initiated.
  3. Time - Time in seconds.

If a fault disappears for any reason after DTC has been recorded permanently by ECM, DTC information will be retained by ECM. Each time the fault occurs, first counter will advance one. Each trip completed without a reoccurrence, a second counter will count down from 3 to zero. When second counter has reached zero, MIL will extinguish (if illuminated) and a third counter will start counting down. The third counter counts number of warm-up cycles (starting at 40). A warm-up cycle is when engine temperature is less than 104°F (40°C) at engine start and exceeds 183°F (84°C). When third counter reaches zero, DTC is erased from ECM memory. If a fault reoccurs, the second and third counter revert to their original settings and the first counter advances one.

Faults are recorded in ECM memory in the form of Diagnostic Trouble Codes (DTCs). Codes can be displayed using Volvo Scan Tool (998-8686 ) or generic scan tester connected to On-Board Diagnostics II (OBD-II) Data Link Connector (DLC). DLC is located in center console to right of parking brake lever. (Схема №1)

DTC 112: FAULT IN ECM

If ECM detects a fault in ROM/EPROM or RAM memory circuits, circuit for ECM temperature sensor, knock control circuit, or ECT sensor circuit NTC coupling, DTC 112 is set. If fault is permanent and signal is faulty, replace ECM. If fault is intermittent, erase DTC. If DTC reoccurs, check ECM connector for good terminal contact. If terminal contact is okay, replace ECM.

DTC 115, 125, 135, 145, 155 OR 165: FUEL INJECTOR PROBLEM

  1. If an injector circuit is shorted to ground or voltage, or if there is a break in the circuit, ECM interprets this as a fault and sets DTC for appropriate injector. If injector signal is too high, check for signal wire shorted to voltage or defective injector. If injector signal is too low, check for signal wire shorted to ground. If signal is missing, check for open circuit in signal or power lead, resistance in terminals, or defective injector.
  2. Check status message on Volvo Scan Tool (998-8686 ). If status message is PERMANENT FAULT, SIGNAL TOO HIGH, go to next step. If status message is PERMANENT FAULT, SIGNAL TOO LOW, go to step 4). If status message is PERMANENT FAULT, SIGNAL MISSING, go to step 5). If status message is INTERMITTENT FAULT, SIGNAL TOO HIGH or INTERMITTENT FAULT, SIGNAL TOO LOW, go to step 8). If status message is INTERMITTENT FAULT, SIGNAL MISSING, go to step 9).
  3. Turn ignition off. Disconnect injector connector. Connect ohmmeter between injector terminals No. 1 and 2. If ohmmeter does not indicate about 16 ohms, install new injector. If ohmmeter indicates about 16 ohms, check wiring between injector connector terminal No. 2 and ECM connector terminal A10 (DTC 115), A24 (DTC 125), A23 (DTC 135), A43 (DTC 145), A38 (DTC 155), or A9 (DTC 165) for a short to voltage.
  4. To check for a PERMANENT FAULT, SIGNAL TOO LOW, check wiring between injector connector terminal No. 2 and ECM connector terminal A10 (DTC 115), A24 (DTC 125), A23 (DTC 135), A43 (DTC 145), A38 (DTC 155), or A9 (DTC 165) for a short to ground.
  5. To check for a PERMANENT FAULT, SIGNAL MISSING, turn ignition off, disconnect injector, and turn ignition on. Connect voltmeter between injector connector terminal No. 1 and ground. If battery voltage is present, go to next step. If battery voltage is not present, check wiring between injector connector terminal No. 1 and main relay connector terminal No. 3 for an open circuit.
  6. Ensure ignition is on. Connect voltmeter between injector connector terminal No. 2 and ground. If voltmeter reads about 6 volts, go to next step. If voltmeter does not read about 6 volts, turn ignition off. Check ECM connector for good terminal contact. Reconnect ECM. Turn ignition on. Connect voltmeter between injector connector terminal No. 2 and ground. If voltmeter reads about 6 volts, fault was caused by poor ECM connector contact. If voltmeter does not read about 6 volts, check wiring between injector connector terminal No. 2 and ECM connector terminal A10 (DTC 115), A24 (DTC 125), A23 (DTC 135), A43 (DTC 145), A38 (DTC 155), or A9 (DTC 165) for an open circuit.
  7. Turn ignition off. Disconnect injector connector. Connect ohmmeter between injector connector terminals No. 1 and 2. If ohmmeter reads about 16 ohms, DTC is caused by poor contact in injector or ECM connector. If ohmmeter does not read about 16 ohms, replace injector.
  8. To check for an INTERMITTENT FAULT, SIGNAL TOO HIGH, check wiring between terminal No. 2 and ECM connector terminal A10 (DTC 115), A24 (DTC 125), A23 (DTC 135), A43 (DTC 145), A38 (DTC 155), or A9 (DTC 165) for an intermittent short to voltage. To check for an INTERMITTENT FAULT, SIGNAL TOO LOW, check wiring between injector connector terminal No. 2 and ECM connector terminal A10 (DTC 115), A24 (DTC 125), A23 (DTC 135), A43 (DTC 145), A38 (DTC 155), or A9 (DTC 165) for an intermittent short to ground.
  9. To check for an INTERMITTENT FAULT, SIGNAL MISSING, check injector and/or ECM connector for good terminal contact. Check wiring between injector terminal No. 1 and main relay No. 3 for an intermittent open circuit. Check wiring between injector connector terminal No. 2 and ECM connector terminal A10 (DTC 115), A24 (DTC 125), A23 (DTC 135), A43 (DTC 145), A38 (DTC 155), or A9 (DTC 165) for an intermittent open circuit.

DTC 121: MAF SIGNAL

  1. If signal from MAF sensor is less than .2 volt or greater than 2.2 volts at idle, or is considered incorrect according to RPM and throttle angle, this is interpreted by ECM as a fault and DTC 121 is set. If fault is permanent and signal is too low, go to step 9). If fault is permanent and signal is too high, go to step 4). If fault is intermittent, go to next step.
  2. If fault is intermittent and signal is too high, check all wiring and connectors for loose contacts and open circuits. Check wiring between MAF sensor connector terminal No. 1 and ECM connector terminal A3 for an intermittent open circuit. Check wiring between MAF sensor terminal No. 2 and ECM connector terminal A5 for an intermittent open circuit. Also, check wiring between MAF sensor terminal No. 4 and ECM connector terminal A4 for an intermittent short to voltage. Repair as necessary.
  3. If fault is intermittent and signal is low, ensure fresh air intake is intact, and upper and lower charge air cooler pipes are correctly attached. Check wiring between main relay connector terminal No. 3 and MAF sensor connector terminal No. 3 for an intermittent open circuit. Also check wiring between MAF sensor connector terminal No. 4 and ECM connector terminal A4 for an intermittent open or short circuit to ground.
  4. Turn ignition off. Wait about 150 seconds and disconnect MAF sensor. Connect ohmmeter between MAF sensor connector terminal No. 1 and ground. If ohmmeter reads about zero ohms, go to next step. If ohmmeter does not indicate about zero ohms, check ECM connector for good terminal contact. Repair as necessary. Repeat test. If ECM connector terminal contact is okay, and/or ohmmeter still does not read about zero ohms, check wiring between MAF sensor connector terminal No. 1 and ECM connector terminal A3 for an open circuit.
  5. Ensure ignition is off and MAF sensor is disconnected. Connect ohmmeter between MAF sensor connector terminal No. 2 and ground. If ohmmeter indicates about zero ohms, go to step 7). If ohmmeter does not indicate about zero ohms, go to next step.
  6. Ensure ignition is off and MAF sensor is disconnected. Ensure ECM connector terminals are not oxidized and make good contact. Reconnect ECM. Connect ohmmeter between MAF sensor connector terminal No. 2 and ground. If ohmmeter indicates about zero ohms, go to next step. If ohmmeter does not indicate about zero ohms, check wiring between MAF sensor connector terminal No. 2 and ECM connector terminal A5 for an open circuit.
  7. Ensure ignition is on and MAF sensor is disconnected. Connect voltmeter between MAF sensor connector terminal No. 4 and ground. If voltmeter indicates 0-1 volt, go to next step. If voltmeter does not indicate 0-1 volt, check wiring between MAF sensor connector terminal No. 4 and ECM connector terminal A4 for a short to voltage. If voltage reading is still incorrect after repair, or short to voltage is not found, replace MAF sensor.
  8. Turn ignition off and reconnect MAF sensor. Turn ignition on. Connect voltmeter between MAF sensor connector terminals No. 2 and 4. If voltmeter indicates about .1-.2 volt, DTC is setting because of poor contact in MAF sensor connector and/or ECM connector. If voltmeter does not indicate about .1-.2 volt, replace MAF sensor.
  9. Ensure ignition is off. Ensure fresh air hoses and upper and lower charge air pipes are undamaged and securely connected. If hoses and pipes are okay, disconnect MAF sensor. Turn ignition on. Connect voltmeter between MAF sensor connector terminal No. 3 and ground. If battery voltage is present, go to next step. If battery voltage is not present, check wiring between MAF sensor connector terminal No. 3 and main relay connector terminal No. 3 for an open circuit.
  10. Ensure ignition is off. Wait 150 seconds, then disconnect MAF sensor. Connect ohmmeter between MAF sensor connector terminal No. 4 and ground. If ohmmeter indicates 9-11 k/ohms, go to next step. If ohmmeter shows about zero ohms, check wiring between MAF sensor connector terminal No. 4 and ECM connector terminal A4 for a short to ground. If ohmmeter shows infinite resistance, check wiring between MAF sensor connector terminal No. 4 and ECM connector terminal A4 for an open circuit.
  11. Turn ignition off. Reconnect MAF sensor connector. Turn ignition on. Connect voltmeter between MAF sensor connector terminals No. 4 and 2. If voltmeter shows .1-.2 volt, check for poor contact in MAF sensor connector and/or ECM connector. If voltmeter does not show .1-.2 volt, test system using a known-good MAF sensor.

DTC 123: ENGINE COOLANT TEMPERATURE SENSOR SIGNAL

  1. Check for additional DTCs. If DTCs 314 and 411 are present, go to next step. If DTCs 314 and 411 are not present, go to step 4).
  2. Check common Engine Coolant Temperature (ECT) sensor, Camshaft Position (CMP) sensor, and Throttle Position (TP) sensor terminal A18 on ECM for poor terminal contact. Repair as necessary, then go to next step.
  3. Ensure ignition is off. Ensure all connectors are connected and components are installed. Connect Multimeter (999 6525) with Temperature Box (999 5281) and Temperature Sensor (999 5282). Carefully remove expansion tank cover. Using a hose clip, clamp hose between radiator and thermostat housing. Disconnect hose from thermostat housing. Insert sensor in thermostat housing and reinstall hose. Remove hose clip. Start and run engine so it reaches normal operating temperature and thermostat opens. Using scan tool, go into scrolling values. Read off engine coolant temperature. If engine coolant temperature is within normal range, system is okay. If engine coolant temperature is not within normal range, check engine cooling system.
  4. If status message reads PERMANENT FAULT, SIGNAL TOO HIGH, go to next step. If status message reads PERMANENT FAULT, SIGNAL TOO LOW, go to step 11). If status message reads PERMANENT FAULT, FAULTY SIGNAL, go to step 12). If status message reads INTERMITTENT FAULT, SIGNAL TOO HIGH, go to step 18). If status message reads INTERMITTENT FAULT, SIGNAL TOO LOW, check wiring between ECT sensor terminal No. 1 and ECM terminal A31. Repair as necessary. NOTE: Before testing, disconnect engine cooling fan relay connector "A". DTC 514 (engine cooling fan half speed) signal will be set. After testing, reattach connector.
  5. Turn ignition off. Wait about 2 minutes. Disconnect ECT sensor. Connect ohmmeter between ECT sensor connector terminal No. 2 (ECM side) and ground. Ensure cooling fan run-on is finished before taking resistance measurements. If ohmmeter shows about zero ohms, go to next step. If ohmmeter does not show about zero ohms, go to step 7).
  6. Turn ignition on. Disconnect ECT sensor. Connect voltmeter between ECT sensor terminals No. 1 and 2. If voltmeter reads about 5 volts, go to step 8). If voltmeter reads less than 5 volts, go to step 10). If voltmeter reads greater than 5 volts, check wiring between ECT sensor terminal No. 1 and ECM terminal A31 for a short circuit to voltage, then go to step 9).
  7. Turn ignition off. Disconnect ECT sensor. Disconnect ECM connector and check for poor terminal contact. Repair as necessary. Connect ohmmeter between ECT sensor connector terminal No. 2 (ECM side) and ground. If ohmmeter reads about zero ohms, DTC was caused by poor terminal contact at ECM. If ohmmeter does not read about zero ohms, check wiring between ECT sensor connector terminal No. 2 and ECM terminal A18 for an open circuit.
  8. Turn ignition off. Disconnect ECT sensor. Connect ohmmeter between ECT sensor connector terminals No. 1 and 2 (sensor side). Ohmmeter should read about 2.2 k/ohms at 77°F (25°C). If reading is to specification, DTC is caused by poor terminal contact at ECT sensor connector. If reading is not to specification, replace ECT sensor.
  9. Turn ignition off. Disconnect ECT sensor. Connect ohmmeter between ECT sensor connector terminals No. 1 and 2 (ECT sensor side). If ohmmeter reads about 2.2 k/ohms at 77°F (25°C), ECT sensor is okay. If ohmmeter does not read about 2.2 k/ohms at 77°F (25°C), replace ECT sensor.
  10. Turn ignition off. Disconnect ECT sensor. Disconnect ECM connector and check for poor terminal contact. Repair as necessary. Reconnect ECM connector. Turn ignition on. Connect voltmeter between ECT sensor connector terminals No. 1 and 2 (ECM side). If voltmeter reads about 5 volts, DTC was caused by poor terminal contact at ECM connector. If voltmeter does not read about 5 volts, check wiring between ECT sensor connector terminal No. 1 and ECM terminal A31 for an open circuit. Repair as necessary.
  11. Turn ignition on. Using scan tool, go into scrolling values. Disconnect ECT sensor. Using scan tool, read off voltage across ECT sensor. If scan tool reads about 5 volts, replace ECT sensor. If scan tool does not read about 5 volts, check wiring between ECT sensor connector terminal No. 1 and ECM terminal A31 for a short to ground.
  12. Ensure ignition is off. Connect Multimeter (999 6525 ) with Temperature Box (999 5281 ) and Temperature Sensor (999 5282 ). Carefully remove expansion tank cover. Using a hose clip, clamp hose between radiator and thermostat housing. Disconnect hose from thermostat housing. Insert sensor in thermostat housing and reinstall hose. Remove hose clip. Using scan tool, go into scrolling values. Start and run engine so it reaches normal operating temperature and thermostat opens. Read off engine coolant temperature. If engine coolant temperature is within normal range, go to next step. If engine coolant temperature is not within normal range, go to step 14).
  13. This DTC can be stored if thermostat is defective or if tolerance of ECT sensor is incorrect within measured range. Using scan tool, read off frozen values. If frozen value for ECT sensor is outside its range, then ECT sensor is defective. Ensure thermostat opens at correct temperature. Replace both ECT sensor and thermostat if no faults are detected in either component.
  14. Turn ignition on. Using scan tool, go into scrolling values list. Read off voltage across ECT sensor. If reading is about 5 volts, go to step 16). If reading is not about 5 volts, go to next step.
  15. Turn ignition off. Disconnect ECT sensor. Disconnect ECM connector and check for poor terminal contact. Repair as necessary. Reconnect ECM connector. Turn ignition on. Using scan tool, go into scrolling values list. Read off voltage across ECT sensor. If about 5 volts are present, DTC was caused by poor terminal contact at ECM connector. If about 5 volts are not present, check wiring between ECT sensor terminal No. 1 and ECM terminal A31 for a short circuit.
  16. Turn ignition off. Wait about 2 minutes. Disconnect ECT sensor. Connect ohmmeter between ECT sensor terminal No. 2 (ECM side) and ground. If ohmmeter reads zero ohms, replace ECT sensor. If ohmmeter does not read zero ohms, go to next step.
  17. Turn ignition off. Disconnect ECT sensor. Disconnect ECM connector and check for poor terminal contact. Repair as necessary. Reconnect ECM connector. Connect ohmmeter between ECT sensor connector terminal No. 2 (ECM side) and ground. If ohmmeter reads about zero ohms, DTC was caused by poor terminal contact at ECM connector. If ohmmeter does not read about zero ohms, check wiring between ECT sensor terminal No. 2 and ECM connector terminal A18 for an open circuit.
  18. Check ECT and ECM connectors for poor terminal contact. Repair as necessary. Check wiring between ECT sensor connector terminal No. 1 and ECM terminal A31 for an intermittent open circuit. Check wiring between ECT sensor connector terminal No. 2 and ECM terminal A18 for an intermittent open circuit. Repair as necessary.

DTC 125: FUEL INJECTOR PROBLEM

See DTC 115, 125, 135, 145, 155 OR 165: FUEL INJECTOR PROBLEM circuit test.

DTC 131: RPM SENSOR SIGNAL

  1. If fault is intermittent, check all connectors for good terminal contact. Repair as necessary. If fault is permanent, turn ignition off. Disconnect RPM sensor. Connect an ohmmeter between RPM sensor connector terminals No. 1 and 2. If ohmmeter shows about 200-500 ohms, go to next step. If ohmmeter does not show 200-500 ohms, replace RPM sensor.
  2. Turn ignition off. Wait 2 minutes. Ensure RPM sensor is disconnected. Connect an ohmmeter between ground and RPM sensor connector terminal No. 2. If ohmmeter reads about zero ohms, go to step 5). If ohmmeter does not read about zero ohms, go to next step.
  3. Turn ignition off. Disconnect RPM sensor connector. Ensure ECM connectors and grounds are clean and tight. Reconnect ECM. Connect an ohmmeter between ground and RPM sensor connector terminal No. 2. If ohmmeter reads about zero ohms, go to next step. If ohmmeter does not read about zero ohms, check wiring between RPM sensor connector terminal No. 2 and ECM for an open circuit.
  4. Turn ignition off. Disconnect RPM sensor connector at ECM. Connect an ohmmeter between ground and RPM sensor connector terminal No. 1. If ohmmeter reads 15-25 k/ohms, go to step 6). If ohmmeter shows higher resistance, go to next step. If ohmmeter shows about zero ohms, check wiring between RPM sensor connector No. 1 and ECM connector terminal A20 for a short circuit to ground.
  5. Turn ignition off. Disconnect ECM connector. Ensure all terminals are clean and tight. Repair as necessary. Reconnect ECM. Disconnect RPM sensor. Connect an ohmmeter between ground and RPM sensor connector terminal No. 1. If ohmmeter reads 15-25 k/ohms, source of DTC was poor contact at ECM connector. If ohmmeter does not read 15-25 k/ohms, check wiring between RPM sensor and ECM connector terminal A20 for an open circuit.
  6. Turn ignition on. Disconnect RPM sensor connector. Connect voltmeter between RPM sensor connector terminals. If voltmeter reads 1-2 volts, go to next step. If voltmeter does not read 1-2 volts, check wiring between RPM sensor and ECM connector terminal A20 for an open circuit or short to voltage.
  7. Turn ignition off. Clean RPM sensor connector terminals. Attempt to start engine. If engine starts, reason for DTC was poor contact in RPM sensor connector and/or ECM connector. If engine does not start, check connecting flange/flywheel for possible damage and scratches through sensor's holes. If no problem is found on connecting flange/flywheel, retest using new RPM sensor.

DTC 132: BATTERY VOLTAGE SIGNAL TOO LOW OR TOO HIGH

  1. If fault is permanent and voltage is too high, check charging system for signs of excessive charge. If fault is intermittent and voltage is too high, replace voltage regulator.
  2. If fault is permanent and voltage is too low, operate engine at idle. Connect voltmeter to battery. If voltmeter reads 12-15 volts, check wiring between battery and ECM connector terminal A27 for an open circuit. If voltmeter does not read 12-15 volts, check charging system. See GENERATOR & REGULATOR article in ELECTRICAL section. If voltmeter does read 12-15 volts, check wiring between battery and ECM for connector resistance.
  3. If fault is intermittent and voltage is too low, check all ECM and main relay wiring and connectors for looseness and/or contact resistance.

DTC 135: FUEL INJECTOR PROBLEM

See DTC 115, 125, 135, 145, 155 OR 165: FUEL INJECTOR PROBLEM circuit test.

DTC 143 OR 433: KNOCK SENSOR SIGNAL

  1. If fault is permanent, go to next step. If fault is intermittent, turn ignition off. Wait 2 minutes. Disconnect knock sensor(s). Connect ohmmeter between knock sensor connector terminal No. 1 and ground. If ohmmeter reads about one megohm, system is okay. If ohmmeter does not read about one megohm, check wiring between knock sensor terminal No. 1 and ECM connector terminal A2 (DTC 143) or terminal A30 (DTC 433) for a short to ground.
  2. Ensure ignition is still off. Wait 2 minutes. Disconnect knock sensor. Connect an ohmmeter between knock sensor connector terminal No. 2 and ground. If ohmmeter reads about zero ohms, go to step 4). If ohmmeter does not read about zero ohms, go to next step.
  3. Ensure ignition is still off and knock sensor is disconnected. Ensure ECM connector is making good electrical contact and is connected securely to ECM. Connect an ohmmeter between knock sensor connector terminal No. 2 and ground. If ohmmeter reads about zero ohms, DTC was caused by poor contact in ECM connector. If ohmmeter does not read about zero ohms, check wiring between knock sensor connector terminal No. 2 and ECM connector terminal A17 for an open circuit.
  4. Ensure ignition is still off and knock sensor is disconnected. Connect an ohmmeter between knock sensor connector terminal No. 1 and ground. If ohmmeter reads about zero ohms, check wiring between knock sensor connector terminal No. 1 and ECM connector terminal A2 (DTC 143) or terminal A30 (DTC 433) for short to ground. If ohmmeter reads about one megohm, go to step 6). If ohmmeter reads infinite resistance, go to next step.
  5. Ensure ignition is still off and knock sensor is disconnected. Ensure ECM connector terminals are free of resistance and oxidation. Reconnect ECM. Connect an ohmmeter between knock sensor connector terminal No. 1 and ground. If ohmmeter reads about one megohm, DTC is caused by poor contact at ECM connector. If ohmmeter does not read about one megohm, check for open circuit in wiring between knock sensor connector terminal No. 1 and ECM connector terminal A2 (DTC 143) or terminal A30 (DTC 433).
  6. Reconnect knock sensor(s). Start and warm up engine. Increase engine speed to 3500 RPM. Use Volvo Scan Tool (998-8686 ) to check knock sensor value (scrolling values list). If knock sensor value is 2-6 at speeds greater than 3500 RPM, source of DTC is poor contact at knock sensor connector. If knock sensor value is not 2-6 at speeds greater than 3500 RPM, test system using a new knock sensor.

DTC 145: FUEL INJECTOR PROBLEM

See DTC 115 , 125, 135, 145, 155 OR 165: FUEL INJECTOR PROBLEM circuit test.

DTC 153: REAR HO2S SIGNAL

  1. If fault is permanent or intermittent and signal is too high, perform diagnosis as per DTC 212. If fault is permanent and signal is too low, go to next step. If fault is permanent and signal is faulty, go to step 5). If fault is permanent and signal is missing, go to step 6). If fault is intermittent and signal is too low, go to step 9). If fault is intermittent and signal is faulty, go to step 10). If fault is intermittent and signal is missing, go to step 11).
  2. Connect Breakout Box (981-3190) to ECM. Turn ignition on. Connect voltmeter between breakout box pins No. 33 and 42. If voltmeter reads about .7 volt, go to next step. If voltmeter does not read about .7 volt, disconnect front HO2S connector. Turn ignition on. Recheck voltage between breakout box pins. If voltmeter reads about .7 volt, install new front HO2S. If voltmeter does not read about .7 volt, disconnect rear HO2S and repeat test. If voltmeter reads about .7 volt, install new rear HO2S. If voltmeter does not read about .7 volt, check wiring between front HO2S terminal No. 3 and ECM connector terminal A33, and wiring between rear HO2S terminal No. 3 and ECM connector terminal A19 for a short to ground.
  3. Turn ignition on. Connect voltmeter between breakout box pins No. 32 and 42. If voltage is about 1.2 volts, go to next step. If voltage is not about 1.2 volts, turn ignition off. Disconnect front HO2S connector. Repeat test. If voltage is now about 1.2 volts, replace front HO2S. If voltage is not about 1.2 volts, check wiring between front HO2S terminal No. 4 and ECM connector terminal A33 for a short to ground.
  4. Turn ignition off. Disconnect rear HO2S connector. Repeat test. Connect voltmeter between breakout box pins No. 34 and 42. If voltage is now about 1.2 volts, replace rear HO2S. If voltage is not about 1.2 volts, check wiring between rear HO2S terminal No. 4 and ECM connector terminal A34 for a short to ground.
  5. Turn ignition off. Wait 2 minutes. Disconnect rear HO2S connector. Connect ohmmeter between HO2S connector terminals No. 3 and 4. If at least 50 k/ohms are present, check wiring between rear HO2S terminal No. 4 and control module connector terminal A34 for a short circuit. If at least 50 k/ohms are not present, replace rear HO2S.
  6. Turn ignition off. Wait 2 minutes. Disconnect rear HO2S connector. Connect ohmmeter between HO2S connector terminals No. 4 and ground. If at least 50 k/ohms are present, go to next step. If at least 50 k/ohms are not present, check HO2S and ECM connectors for poor terminal contact. Repair as necessary. Repeat test. If at least 50 k/ohms are present, system is okay, If at least 50 k/ohms are not present, check wiring between rear HO2S connector terminal No. 4 and ECM connector terminal A34 for an open circuit.
  7. Ensure ignition is off. Connect ohmmeter between rear HO2S connector terminal No. 3 and ground. If ohmmeter reads about 140 ohms, go to next step. If ohmmeter does not read about 140 ohms, check HO2S and ECM connectors for poor terminal contact. Repair as necessary. Repeat test. If ohmmeter reads about 140 ohms, system is okay, If ohmmeter does not read about 140 ohms, check wiring between rear HO2S connector terminal No. 3 and ECM connector terminal A33 for an open circuit.
  8. Reconnect HO2S. Start and idle engine. Using scan tool, go into scrolling values list. If DTC is intermittent status, DTC was caused by poor terminal contact. If rear HO2S signal is not to specification, replace rear HO2S.
  9. Check wiring between front HO2S connector terminal No. 4 and ECM connector terminal A32 for an intermittent short to ground. Check wiring between front HO2S terminal No. 3 and ECM connector terminal A33, and between rear HO2S terminal No. 3 and ECM connector terminal A19 for an intermittent short circuit. Check wiring between rear HO2S terminal No. 4 and ECM connector terminal A34 for an intermittent short to ground. Repair as necessary.
  10. Check wiring between front HO2S connector terminal No. 4 and ECM connector terminal A34 for an intermittent short to wiring harness between front HO2S terminal No. 3 and ECM connector terminal A19. Repair as necessary.
  11. Check wiring between rear HO2S terminal No. 4 and ECM connector terminal A34 for an intermittent short circuit. Check wiring between rear HO2S terminal No. 3 and ECM connector terminal A19 for an intermittent open circuit. Check ECM and rear HO2S connectors for poor terminal contact. Repair as necessary.

DTC 155: FUEL INJECTOR PROBLEM

See DTC 115 , 125, 135, 145, 155 OR 165: FUEL INJECTOR PROBLEM circuit test.

DTC 165: FUEL INJECTOR PROBLEM

See DTC 115 , 125, 135, 145, 155 OR 165: FUEL INJECTOR PROBLEM circuit test.

DTC 211: CO POTENTIOMETER

  1. If fault is permanent and signal is too high, go to next step. If fault is permanent and signal is too low, go to step 10). If fault is intermittent and signal is too high, go to step 12). If fault is intermittent and signal is too low, go to step 13).
  2. Turn ignition off. Disconnect CO potentiometer connector. Turn ignition on. Connect voltmeter between CO potentiometer connector terminal No. 3 and ground. If about 5 volts are present, go to next step. If less than 5 volts are present, go to step 7). If greater than 5 volts are present, note that CO potentiometer power lead is connected to A/C pressure sensor power lead inside ECM. If any problem is present in either lead both components will be affected. Check for a short circuit to voltage in wiring between CO potentiometer connector terminal No. 3 and ECM connector terminal B1, and between A/C pressure sensor terminal No. 3 and ECM connector terminal B29.
  3. Ensure ignition is off and CO potentiometer is disconnected. Connect ohmmeter between CO potentiometer connector terminal No. 1 and ground. If ohmmeter reads about zero ohms, go to next step. If ohmmeter does not read about zero ohms, check ECM connector for poor terminal contact. Repair as necessary. If terminal contact is okay, connect ohmmeter between CO potentiometer connector terminal No. 1 and ground. If ohmmeter reads about zero ohms, cause of DTC was poor terminal contact at ECM connector. If ohmmeter does not read about zero ohms, check for an open circuit in wiring between CO potentiometer terminal No. 1 and ECM terminal B28. Repair as necessary.
  4. Ensure ignition is on and CO potentiometer is disconnected. Connect voltmeter between CO potentiometer connector terminal No. 2 and ground. If about 5 volts are present, go to step 6). If less than 5 volts are present, go to next step. If greater than 5 volts are present, check for short circuit to voltage in wiring between CO potentiometer terminal No. 2 and ECM connector terminal B32. Repair as necessary.
  5. Ensure ignition is off and CO potentiometer is disconnected. Check ECM connector for contact resistance. Repair as necessary. Reconnect ECM connector. Turn ignition on. Connect voltmeter between CO potentiometer connector terminal No. 2 and ground. If about 5 volts are present, DTC was caused by poor ECM terminal contact. If about 5 volts are not present, check for an open circuit in wiring between CO potentiometer terminal No. 2 and ECM connector terminal B32.
  6. Ensure CO potentiometer is disconnected. Remove seal from CO potentiometer plug hole. Drill 2 .079 (2 mm) holes in plug. Pull out plug. Reconnect CO potentiometer connector. Start and idle engine. Using scan tool, read CO potentiometer value. Turn adjustment screw clockwise to lower voltage. If reading is okay, adjust CO. See ADJUSTMENTS article. If reading is not okay, replace CO potentiometer.
  7. Ensure ignition is off and CO potentiometer is disconnected. Wait about 2 minutes. Connect ohmmeter between CO potentiometer connector terminal No. 3 and ground. If ohmmeter does not read about zero ohms, go to step 9). If ohmmeter reads about zero ohms, go to next step.
  8. Ensure ignition is off and CO potentiometer is disconnected. Disconnect A/C pressure sensor. Connect ohmmeter between CO potentiometer connector terminal No. 3 and ground. If ohmmeter reads .2-1.5 k/ohms, replace A/C pressure sensor. If ohmmeter does not read .2-1.5 k/ohms, ensure CO potentiometer is connected to A/Cpressure sensor power lead in ECM. If a problem is present in either power lead, both components will be affected. Check for short circuit to voltage in wiring between CO potentiometer terminal No. 3 and ECM terminal B1, and A/C pressure sensor terminal No. 3 and ECM terminal B29. Repair as necessary.
  9. Ensure ignition is off and CO potentiometer is disconnected. Check ECM connector terminals for poor terminal contact and repair as necessary. Reconnect ECM connector. Connect ohmmeter between CO potentiometer connector terminal No. 3 and ground. If ohmmeter reads about .2-1.5 k/ohms, DTC was caused by poor terminal contact. If ohmmeter does not read about .2-1.5 k/ohms, check for open circuit in wiring between CO potentiometer terminal No. 3 and ECM connector terminal B1. Repair as necessary.
  10. If fault is permanent and signal is too low, turn ignition off. Disconnect CO potentiometer. Turn ignition on. Connect voltmeter between CO potentiometer connector terminal No. 2 and ground. If voltmeter reads 5 volts, go to next step. If voltmeter does not read 5 volts, check for short circuit to ground in wiring between CO potentiometer terminal No. 2 and ECM connector terminal B32.
  11. Ensure CO potentiometer is disconnected. Remove seal from CO potentiometer plug hole. Drill 2 .079 (2 mm) holes in plug. Pull out plug. Reconnect CO potentiometer connector. Start and idle engine. Using scan tool, read off CO potentiometer value. Turn adjustment screw counter-clockwise to increase voltage. If reading is okay, adjust CO. See ADJUSTMENTS article. If reading is not okay, replace CO potentiometer.
  12. If fault is intermittent and signal is too high, check CO potentiometer and ECM connectors for poor terminal contact. Also, check for an intermittent open circuit in wiring between CO potentiometer terminal No. 3 and ECM connector terminal B1, and between CO potentiometer terminal No. 1 and ECM connector terminal B28. Check for intermittent open circuit or short circuit to voltage in wiring between CO potentiometer terminal No. 2 and ECM connector terminal B32. Since CO potentiometer power lead is connected to A/C pressure sensor power lead inside ECM, also check for short circuit to ground or voltage in wiring between CO potentiometer terminal No. 3 and ECM connector terminal B1, and between A/C pressure sensor terminal No. 3 and ECM connector terminal B29. Repair as necessary.
  13. If fault is intermittent and signal is too low, check for an intermittent short circuit to ground in wiring between CO potentiometer terminal No. 2 and ECM connector terminal B32. Repair as necessary.

DTC 212: FRONT HO2S SIGNAL

  1. If fault is permanent and signal is too high, go to next step. If fault is permanent and signal is too low, go to step 5). If fault is permanent and signal is faulty, go to step 8). If fault is permanent and signal is missing, go to step 9). If fault is intermittent and signal is too low, go to step 12). If fault is intermittent and signal is faulty, go to step 13). If fault is intermittent and signal is missing, go to step 14). If fault is intermittent and signal is too high, go to step 15).
  2. Connect Breakout Box (981-3190) to ECM. Turn ignition on. Connect voltmeter between breakout box pins No. 33 and 42. If voltmeter reads about .7 volt, go to next step. If voltmeter does not read about .7 volt, disconnect front HO2S connector. Turn ignition on. Recheck voltage between breakout box pins. If voltmeter reads about .7 volt, install new front HO2S. If voltmeter does not read about .7 volt, disconnect front and rear HO2S connectors and repeat test. If voltmeter reads about .7 volt, install new rear HO2S. If voltmeter does not read about .7 volt, check wiring between front HO2S terminal No. 3 and ECM connector terminal A33, and wiring between rear HO2S terminal No. 3 and ECM connector terminal A19 for a short to ground.
  3. Turn ignition on. Connect voltmeter between breakout box pins No. 32 and 42. If voltage is about 1.2 volts, go to next step. If voltage is not about 1.2 volts, turn ignition off. Disconnect front HO2S connector. Repeat test. If voltage is now about 1.2 volts, replace front HO2S. If voltage is not about 1.2 volts, check wiring between front HO2S terminal No. 4 and ECM connector terminal A32 for a short to voltage.
  4. Turn ignition off. Disconnect rear HO2S connector. Connect voltmeter between breakout box pins No. 34 and 42. If voltage is now about 1.2 volts, replace rear HO2S. If voltage is not about 1.2 volts, check wiring between rear HO2S terminal No. 4 and ECM connector terminal A34 for a short to voltage.
  5. Connect Breakout Box (981-3190) to ECM. Turn ignition on. Connect voltmeter between breakout box pins No. 33 and 42. If voltmeter reads about .7 volt, go to next step. If voltmeter does not read about .7 volt, disconnect front HO2S connector. Turn ignition on. Recheck voltage between breakout box pins. If voltmeter reads about .7 volt, install new front HO2S. If voltmeter does not read about .7 volt, disconnect rear HO2S and repeat test. If voltmeter reads about .7 volt, install new rear HO2S. If voltmeter does not read about .7 volt, check wiring between front HO2S terminal No. 3 and ECM connector terminal A33, and wiring between rear HO2S terminal No. 3 and ECM connector terminal A19 for a short to ground.
  6. Turn ignition on. Connect voltmeter between breakout box pins No. 32 and 42. If voltage is about 1.2 volts, go to next step. If voltage is not about 1.2 volts, turn ignition off. Disconnect front HO2S connector. Repeat test. If voltage is now about 1.2 volts, replace front HO2S. If voltage is not about 1.2 volts, check wiring between front HO2S terminal No. 4 and ECM connector terminal A33 for a short to ground.
  7. Turn ignition off. Disconnect rear HO2S connector. Repeat test. Connect voltmeter between breakout box pins No. 34 and 42. If voltage is now about 1.2 volts, replace rear HO2S. If voltage is not about 1.2 volts, check wiring between rear HO2S terminal No. 4 and ECM connector terminal A34 for a short to ground.
  8. Turn ignition off. Wait 2 minutes. Disconnect front HO2S connector. Connect ohmmeter between HO2S connector terminals No. 3 and 4. If at least 50 k/ohms are present, check wiring between front HO2S terminal No. 4 and control module connector terminal A34 for a short circuit. If at least 50 k/ohms are not present, replace front HO2S.
  9. Turn ignition off. Wait 2 minutes. Disconnect front HO2S connector. Connect ohmmeter between HO2S connector terminal No. 4 and ground. If at least 50 k/ohms are present, go to next step. If at least 50 k/ohms are not present, check HO2S and ECM connectors for good terminal contact. Repair as necessary. Repeat test. If at least 50 k/ohms are present, system is okay, If at least 50 k/ohms are not present, check wiring between rear HO2S connector terminal No. 4 and ECM connector terminal A32 for an open circuit.
  10. Ensure ignition is off. Connect ohmmeter between front HO2S connector terminal No. 3 and ground. If ohmmeter reads about 140 ohms, go to next step. If ohmmeter does not read about 140 ohms, check HO2S and ECM connectors for good terminal contact. Repair as necessary. Repeat test. If ohmmeter reads about 140 ohms, system is okay, If ohmmeter does not read about 140 ohms, check wiring between rear HO2S connector terminal No. 3 and ECM connector terminal A33 for an open circuit.
  11. Start and idle engine. Using scan tool, go into scrolling values list. If rear HO2S signal rises above its middle value of .47 volt then maintains between .1-.9 volt within about 10 minutes, DTC was caused by poor terminal contact. If rear HO2S signal is not to specification, replace rear HO2S.
  12. Check wiring between front HO2S connector terminal No. 4 and ECM connector terminal A32 for an intermittent short to ground. Check wiring between front HO2S terminal No. 3 and ECM connector terminal A33, and between rear HO2S terminal No. 3 and ECM connector terminal A19 for an intermittent short circuit. Check wiring between rear HO2S terminal No. 4 and ECM connector terminal A34 for an intermittent short to ground. Repair as necessary.
  13. Check wiring between front HO2S connector terminal No. 4 and ECM connector terminal A32 for an intermittent short to wiring harness between front HO2S terminal No. 3 and ECM connector terminal A33. Repair as necessary.
  14. Check wiring between front HO2S terminal No. 4 and ECM connector terminal A32 for an intermittent open circuit. Check wiring between front HO2S terminal No. 3 and ECM connector terminal A33 for an intermittent open circuit. Also check ECM and front HO2S connectors for loose connections.
  15. Check wiring between front HO2S connector terminal No. 4 and ECM connector terminal A32 for an intermittent short to voltage. Check wiring between front HO2S terminal No. 3 and ECM connector terminal A33, and between rear HO2S terminal No. 3 and ECM connector terminal A19 for an intermittent short circuit to voltage. Check wiring between rear HO2S terminal No. 4 and ECM connector terminal A34 for an intermittent short to voltage.

DTC 214: RPM SENSOR SIGNAL SPORADIC

  1. Check RPM sensor and ECM connectors for loose connection, contact resistance and oxidation. Repair as necessary. Check wiring for short circuit to ground or voltage.
  2. If all wiring and connections are okay, check connecting flange/flywheel through sensor hole for damage and scratches. If no damage is present, retest using new RPM sensor.

DTC 223 OR 245: IAC VALVE SIGNAL

  1. If fault is permanent and signal is too high, go to next step. If fault is permanent and signal is too low, go to step 3). If fault is intermittent and signal is too high, go to step 6). If fault is intermittent and signal is too low, go to step 7). If fault is permanent and signal is missing, go to step 9). If fault is intermittent and signal is missing, check all connectors for good terminal contact. Repair as necessary.
  2. Turn ignition off. Disconnect IAC valve. Turn ignition on. Connect test light between ground and IAC valve connector terminal No. 3 (DTC 223) or terminal No. 1 (DTC 245). If test light does not come on, replace valve. If test light comes on (DTC 223), check wiring between IAC valve connector terminal No. 3 and ECM connector terminal A11 for a short circuit to voltage. If test light comes on (DTC 245), check wiring between IAC valve connector terminal No. 1 and ECM connector terminal A25 for a short circuit to voltage.
  3. If fault is permanent and signal is too low, turn ignition off. Disconnect IAC valve. Turn ignition on. Connect voltmeter between IAC valve connector terminal No. 2 and ground. If voltmeter shows battery voltage, go to next step. If voltmeter does not show battery voltage, check wiring between main relay connector terminal No. 3 and IAC valve connector terminal No. 2 for an open circuit. If there is an open circuit in voltage lead, both DTCs 223 and 245 will be set.
  4. Turn ignition off. Wait about 2 minutes. Disconnect IAC valve connector. Connect an ohmmeter between IAC valve connector terminals No. 1 and 3. If ohmmeter reads 200 k/ohms, go to next step. If ohmmeter reads 70-100 k/ohms, check wiring between IAC valve terminal No. 3 and ECM connector terminal A11 for a short to ground. Repair as necessary. If ohmmeter shows about zero ohms on DTC 223, check wiring between IAC valve connector terminal No. 3 and ECM connector terminal A11 for a short to wiring between IAC valve connector terminal No. 1 and ECM connector terminal A25. Repair as necessary.
  5. Turn ignition off. Disconnect IAC valve. Connect ohmmeter between IAC valve connector terminals No. 1 and 2, then between terminals No. 2 and 3. If ohmmeter reads 9-14 ohms in both cases, cause of DTC is poor contact in IAC valve connector. Repair as necessary. If ohmmeter does not read 9-14 ohms in both cases, test using new IAC valve.
  6. If fault is intermittent and signal is too high on DTC 223, check wiring between IAC valve connector terminal No. 3 and ECM connector terminal A11 for an intermittent short to voltage or intermittent short circuit to coil signal voltage. On DTC 245, check wiring between IAC valve connector terminal No. 1 and ECM connector terminal A25 for an intermittent short to voltage or intermittent short circuit to coil signal voltage.
  7. If fault is intermittent and signal is too low on DTC 245, go to next step. On DTC 223, check IAC valve and ECM connectors for contact resistance and oxidation. Repair as necessary. Check wiring between main relay connector terminal No. 3 and IAC valve connector terminal No. 2 for an intermittent open circuit. Also check wiring between IAC valve connector terminal No. 3 and ECM connector terminal A11 for an intermittent open circuit or short circuit to ground.
  8. On DTC 245, check IAC valve and ECM connectors for contact resistance and oxidation. Repair as necessary. Check wiring between main relay connector terminal No. 3 and IAC valve connector terminal No. 2 for an intermittent open circuit. Also check wiring between IAC valve connector terminal No. 1 and ECM connector terminal A25 for an intermittent open circuit or short circuit to ground.
  9. If fault is permanent and signal is missing, turn ignition off. Wait about 2 minutes. Disconnect IAC valve. Connect ohmmeter between ground and IAC valve connector terminal No. 3. If ohmmeter does not read 70-100 k/ohms, go to next step. If ohmmeter reads 70-100k/ohms, measure resistance between IAC valve connector terminals No. 1 and 2, then between terminals No. 2 and 3. If ohmmeter reads 9-14 ohms in both cases, DTC was caused by poor terminal contact at IAC valve connector. If ohmmeter does not read 9-14 ohms, replace IAC valve.
  10. Check IAC valve connector terminals and ECM connector terminals for good terminal contact. Repair as necessary. Repeat test. If ohmmeter now reads 70-100 k/ohms, problem was poor terminal contact. If ohmmeter does not read 70-100 k/ohms, check wiring between IAC valve terminal No. 3 and ECM connector terminal A11 for an open circuit.

DTC 225: A/C PRESSURE SENSOR

  1. If fault is permanent and signal is too high, go to next step. If fault is permanent and signal is too low, go to step 6). If fault is intermittent and signal is too high, go to step 11). If fault is intermittent and signal is too low, go to step 12). If fault is permanent and signal is faulty, replace A/C pressure sensor. If fault is intermittent and signal is faulty, check wiring for an intermittent open circuit.
  2. Turn ignition off. Wait about 2 minutes. Disconnect A/C pressure sensor. Connect an ohmmeter between A/C pressure sensor connector terminal No. 1 and ground. If ohmmeter reads about zero ohms, go to step 4). If ohmmeter does not read about zero ohms, go to next step.
  3. Turn ignition off. Disconnect A/C pressure sensor connector. Check ECM connector for oxidation and poor terminal contact. Repair as necessary. Reconnect ECM connector. Connect an ohmmeter between A/C pressure sensor connector terminal No. 1 and ground. If ohmmeter reads about zero ohms, go to next step. If ohmmeter does not read about zero ohms, check wiring between A/C pressure sensor connector terminal No. 1 and ECM connector terminal B28 for an open circuit.
  4. Turn ignition on. Disconnect A/C pressure sensor connector. Connect a voltmeter between A/C pressure sensor connector terminal No. 2 and ground. If voltmeter reads about zero volts, go to next step. If voltmeter does not read about zero volts, check wiring between A/C pressure sensor connector terminal No. 2 and ECM connector terminal B9 for a short to voltage.
  5. Turn ignition off. Connect ohmmeter between A/C pressure sensor connector terminal No. 2 and ground. If ohmmeter does not read about 10 k/ohms, check wiring between A/C pressure sensor terminal No. 2 and ECM connector terminal B9 for an open circuit. If ohmmeter reads about 10 k/ohms, reconnect A/C pressure sensor. Start engine and idle for 15 seconds. Turn A/C and blower on. If scan tool indicates voltage increases when A/C compressor starts, DTC was caused by poor terminal contact. If scan tool does not indicate voltage increase, replace A/C pressure sensor.
  6. If fault is permanent and signal is too low, turn ignition off. Disconnect A/C pressure sensor. Turn ignition on. Connect voltmeter between A/C pressure sensor connector terminal No. 3 and ground. If voltmeter reads less than 5 volts, go to step 8). If voltmeter reads greater than 5 volts, ensure A/C pressure sensor voltage feed wire is connected inside ECM to accelerometer voltage feed. A problem with one wire will affect both. Repair as necessary. If voltmeter reads about 5 volts, check resistance between A/C pressure sensor terminal No. 2 and ground. If ohmmeter reads about 10 k/ohms, go to next step. If ohmmeter does not read about 10 k/ohms, check wiring for a short to ground.
  7. Reconnect A/C pressure sensor. Start and idle engine. Turn A/C and blower on. If scan tool indicates voltage increases when A/C compressor starts, DTC was caused by poor terminal contact. If scan tool does not indicate voltage increase, replace A/C pressure sensor.
  8. Turn ignition off. Disconnect A/C pressure sensor connector. Wait 2 minutes. Connect ohmmeter between A/C pressure sensor connector terminal No. 3 and ground. If ohmmeter reads lower than .2-1.5 k/ohms, go to next step. If ohmmeter reads higher than .2-1.5 k/ohms, check connectors for poor terminal contact. Repair as necessary and repeat test. If reading is still incorrect, check wiring between A/C pressure sensor terminal No. 3 and ECM connector terminal B29 for an open circuit.
  9. Connect ohmmeter between A/C pressure sensor connector terminal No. 3 and ground. If ohmmeter reads .2-1.5 k/ohms, replace accelerometer. If ohmmeter does not read .2-1.5 k/ohms, ensure A/C pressure sensor voltage feed wire is connected inside ECM to accelerometer voltage feeds. A problem with one wire will affect both components. Repair as necessary.
  10. If fault is intermittent and signal is too high, check A/C pressure sensor and ECM connectors for loose connection or contact resistance. Check wiring between A/C pressure sensor connector terminal No. 2 and ECM connector terminal B9 for an intermittent open circuit. Also check wiring between A/C pressure sensor connector terminal No. 1 and ECM connector terminal B28 for an intermittent open circuit or short circuit to ground.
  11. If fault is intermittent and signal is too low, check for an intermittent open circuit or short circuit to ground in wiring between A/C pressure sensor connector terminal No. 3 and ECM connector terminal B29, and wiring between A/C pressure sensor terminal No. 2 and ECM connector terminal B9. Repair as necessary.

DTC 231 OR 232: LONG TERM FUEL TRIM

  1. Check status message on Volvo Scan Tool (998-8686 ). If status message reads LOWER LIMIT, go to step 8). If status message reads UPPER LIMIT, go to next step.
  2. Turn ignition on. Connect voltmeter between MAF sensor connector terminals No. 2 and 4. If voltmeter reads .1-.2 volt, go to next step. If voltmeter does not read .1-.2 volt, retest using new MAF sensor.
  3. Check for air leakage in intake system. Repair as necessary. If air leakage in intake system is not present, go to next step.
  4. Check for air leakage in exhaust system. If there is no air leakage, go to next step. If there is air leakage, repair as necessary.
  5. Check fuel and residual pressure. If fuel and residual pressure are okay, go to next step. If fuel and residual pressure are not okay, repair as necessary.
  6. Test drive vehicle at 1250 RPM on a flat road. Read short term fuel trim and engine speed (RPM) values. If test value varies at about 1.000, go to next step. If test value does not vary at about 1.000, replace pulsation damper.
  7. Connect breakout box to ECM and check ground connections. See COMPUTERIZED ENGINE CONTROLS in SYSTEM/COMPONENT TESTS article. Reconnect ECM. Repair as necessary.
  8. If status message reads LOWER LIMIT, turn ignition on. Connect voltmeter between MAF sensor connectors terminals No. 2 and 4. If voltmeter reads .1-.2 volt, go to next step. If voltmeter does not read .1-.2 volt, test using new MAF sensor.
  9. Check for air leakage in intake and exhaust system. Repair as necessary. Check fuel and residual pressure. Repair as necessary. If there is no air leakage and fuel and residual pressure are okay, go to next step.
  10. Remove hose leading to intake manifold from Canister Purge (CP) valve. Connect vacuum pump to CP valve coupling. If vacuum gauge does not show stable vacuum, repair as necessary. If vacuum gauge does show stable vacuum, go to next step. Check engine oil and fill as necessary.
  11. Start engine and run at idle a few minutes. Using Volvo Scan Tool (998-8686 ), go to scrolling values list and note short term fuel trim value. Disconnect and plug crankcase ventilation. Read off value of fuel trim once again. If value is more or less unchanged, go to next step. If value rises, engine oil is diluted with fuel. Repair as necessary.
  12. Connect breakout box to ECM connector and check grounds. Connect ECM. Check all signals to and from ECM. Repair as necessary.

DTC 233: IDLE AIR TRIM

  1. Check status message on Volvo Scan Tool (998-8686 ). If status message reads UPPER LIMIT, go to next step. If status message reads LOWER LIMIT, go to step 6).
  2. Turn ignition off. Ensure air cleaner, air intake, and hoses and pipes between air cleaner and throttle body are not blocked. Also check connectors for IAC valve. If all components are okay, go to next step. If all components are not okay, repair as necessary.
  3. Turn ignition off. Disconnect IAC valve. Connect an ohmmeter between IAC connector terminals No. 1 and 3. If ohmmeter reads 18-28 ohms, go to next step. If ohmmeter does not read 18-28 ohms, retest using new IAC valve.
  4. Turn ignition off. Remove IAC valve. Hold valve at connector. Turn valve quickly (but carefully) back and forth. Listen for sound of slide striking. CAUTION: To prevent scratching and damage, do not touch slide with a screwdriver or similar tool.
  5. If slide in IAC valve strikes, clean IAC valve and ECM connectors of oxidation or other contact resistance. If slide does not strike, retest using new IAC valve.
  6. Ensure seal on throttle body adjusting screw is good. Ensure throttle spindle is contacting adjustment screw and throttle pulley contact idling stop. Check intake system for air leakage. Repair as necessary. If components are okay, turn ignition on. Using scan tool, activate IAC valve. If a clicking sound is heard, go to next step. If no clicking sound is heard, check connectors for poor terminal contact. Repair as necessary. If terminal contact is okay, go to next step.
  7. Turn ignition off. Disconnect IAC valve. Connect an ohmmeter between IAC valve connector terminal No. 1 and 3. If ohmmeter reads 18-28 ohms, go to next step. If ohmmeter does not read 18-28 ohms, retest using new IAC valve.
  8. Turn ignition off. Remove fresh air intake between air cleaner and throttle body. Check throttle for damage. Repair as necessary. If throttle is not damaged, install new IAC valve.

DTC 251: OUTSIDE TEMPERATURE SENSOR SIGNAL

  1. Check for additional DTCs. If DTCs 123 and 411 are present, go to next step. If DTCs 314 and 411 are not present, go to step 4).
  2. Check common outside temperature sensor and Throttle Position (TP) sensor terminal A18 on ECM for poor terminal contact. Repair as necessary, then go to next step.
  3. Turn ignition off. Reconnect electrical connectors and reinstall components. Turn ignition on. Using scan tool, read off outside temperature. If temperature value is within specification, system is okay. If temperature value is not within specification, no fault is present.
  4. If status message reads PERMANENT FAULT, SIGNAL TOO HIGH, go to next step. If status message reads PERMANENT FAULT, SIGNAL TOO LOW, go to step 11). If status message reads PERMANENT FAULT, FAULTY SIGNAL, go to step 12). If status message reads INTERMITTENT FAULT, SIGNAL TOO HIGH or INTERMITTENT FAULT, SIGNAL SPORADIC, go to step 14). If status message reads INTERMITTENT FAULT, SIGNAL TOO LOW, check wiring between outside temperature sensor terminal No. 1 and ECM terminal A35 for an intermittent short circuit. Repair as necessary.
  5. Turn ignition off. Wait about 2 minutes. Disconnect right outside temperature sensor located in air intake, below grille. Connect ohmmeter between outside temperature sensor connector terminal No. 2 and ground. If ohmmeter reads about zero ohms, go to next step. If ohmmeter does not read about zero ohms, go to step 7).
  6. Turn ignition on. Disconnect temperature sensor. Connect voltmeter between temperature sensor connector terminals No. 1 and 2 (ECM side). If voltmeter reads about 5 volts, go to step 8). If voltmeter reads less than 5 volts, go to step 10). If voltmeter reads greater than 5 volts, check wiring between outside temperature sensor terminal No. 1 and ECM terminal A35 for a short to voltage. Repair as necessary, then go to step 9).
  7. Turn ignition off. Disconnect outside temperature sensor connector. Check ECM connector for poor terminal contact. Repair as necessary. Reconnect ECM. Connect ohmmeter between temperature sensor connector terminal No. 2 (ECM side) and ground. If ohmmeter reads about zero ohms, DTC was caused by poor terminal contact at ECM connector. If ohmmeter does not read about zero ohms, check wiring between outside temperature sensor terminal No. 2 and ECM terminal A18 for an open circuit. Repair as necessary.
  8. Turn ignition off. Disconnect outside temperature sensor connector. Connect ohmmeter between outside temperature sensor terminals No. 1 and 2. If ohmmeter reads about 500 ohms at 77°F (25°C), DTC was caused by poor terminal contact at ECM connector. If ohmmeter does not read about 500 ohms at 77°F (25°C), replace outside temperature sensor.
  9. Turn ignition off. Disconnect outside temperature sensor connector. Connect ohmmeter between outside temperature sensor terminals No. 1 and 2. If ohmmeter reads about 500 ohms at 77°F (25°C), temperature sensor is okay. If ohmmeter does not read about 500 ohms at 77°F (25°C), replace outside temperature sensor.
  10. Turn ignition off. Disconnect outside temperature sensor connector. Check ECM connector for poor terminal contact. Repair as necessary. Reconnect ECM. Turn ignition on. Connect voltmeter between temperature sensor connector terminals No. 1 and 2 (ECM side). If voltmeter reads about 5 volts, DTC was caused by poor terminal contact at ECM connector. If voltmeter does not read about 5 volts, check wiring between outside temperature sensor terminal No. 1 and ECM terminal A35 for a short circuit to voltage.
  11. Turn ignition on. Disconnect right outside temperature sensor located in air intake, below grille. Connect voltmeter between outside temperature sensor connector terminal No. 1 and ground. If voltmeter reads about 5 volts, replace outside temperature sensor. If voltmeter does not read about 5 volts, check wiring between outside temperature sensor terminal No. 1 and ECM terminal A35 for a short to ground. Repair as necessary.
  12. Turn ignition off. Check outside temperature sensor and ECM connectors for poor terminal contact. Repair as necessary. Reconnect connectors. Start and idle engine. Wait about 5 minutes. Using scan tool, read off DTCs. If DTC is still stored with intermittent status, DTC was caused by poor terminal contact at outside temperature sensor and ECM connectors. If DTC is not stored with intermittent status, go to next step.
  13. Turn ignition off. Check outside temperature sensor and ECM connectors for poor terminal contact. Check wiring between outside temperature sensor connector terminal No. 1 and ECM terminal A35 for an intermittent open circuit. Also check wiring between outside temperature sensor connector terminal No. 2 and ECM terminal A18 for an intermittent open circuit. Repair as necessary. Reconnect connectors. Start and idle engine. Wait about 5 minutes. If DTC is stored with intermittent status, system is okay. If DTC is not stored with intermittent status, replace outside temperature sensor.
  14. Check outside temperature sensor and ECM connectors for poor terminal contact. Check wiring between outside temperature sensor connector terminal No. 1 and ECM terminal A35 for an intermittent open circuit. Also check wiring between outside temperature sensor connector terminal No. 2 and ECM terminal A18 for an intermittent open circuit. Repair as necessary.

DTC 311: SPEEDOMETER SIGNAL

  1. Test drive vehicle. If speedometer functions correctly, go to next step. If speedometer does not function correctly, see INSTRUMENT PANEL article in ACCESSORIES/SAFETY EQUIPMENT section.
  2. Ensure ignition is off. Connect breakout box and check ground terminals. Repair as necessary. Shift transmission to Neutral. Raise and support rear of vehicle. Turn ignition on. Connect voltmeter between breakout box pins No. 18 and 28. Rotate rear wheels. If voltmeter reading varies between .5-12 volts, source of DTC is poor contact in ECM connector. If voltmeter reading does not vary between .5-12 volts, go to next step.
  3. If voltage reading remains at zero volts, check for short circuit to ground in wiring between instrument cluster connector terminal A7 and ECM connector terminal B18. If voltage reading remains at about 5 volts, connect test light between breakout box pins No. 18 and 28. If test light comes on, check for a short circuit to voltage in wiring between instrument cluster connector terminal D1 and ECM connector terminal B18. If test light does not come on, check for an open circuit in wiring between instrument cluster connector terminal D1 and ECM connector terminal B18.

DTC 314: CAMSHAFT POSITION SENSOR SIGNAL

  1. Using Volvo Scan Tool (998-8686 ) check status message. If fault is permanent, go to next step. If fault is intermittent, go to step 9).
  2. Turn ignition off. Wait about 2 minutes. Disconnect camshaft position sensor. Connect an ohmmeter between camshaft position sensor connector terminal No. 1 and ground. If ohmmeter reads about zero ohms, go to step 4). If ohmmeter does not read about zero ohms, go to next step.
  3. Turn ignition off. Disconnect ECM connector. Disconnect camshaft position sensor connector. Ensure ECM connector terminals are clean and free of oxidation. Reconnect ECM connector. Connect an ohmmeter between camshaft position sensor terminal No. 1 and ground. If ohmmeter reads about zero ohms, source of DTC is poor contact in ECM connector. If ohmmeter does not read about zero ohms, check wiring between camshaft position sensor connector terminal No. 1 and ECM connector terminal A18 for an open circuit.
  4. Turn ignition on. Disconnect camshaft position sensor connector. Connect voltmeter between camshaft position sensor connector terminal No. 3 and ground. If battery voltage is present, go to step 6). If battery voltage is not present, go to next step.
  5. Turn ignition off. Disconnect camshaft position sensor. Ensure ECM connector terminals are clean and free of oxidation. Reconnect ECM. Turn ignition on. Connect voltmeter between camshaft position sensor connector terminal No. 3 and ground. If voltmeter shows battery voltage, source of DTC is poor contact in ECM connector. If voltmeter does not show battery voltage, check wiring between CMP sensor connector terminal No. 3 and ECM connector terminal A36 for an open circuit.
  6. Turn ignition on. Disconnect camshaft position sensor connector. Connect test light between camshaft position sensor connector terminal No. 2 and ground. If test light does not come on, go to next step. If test light comes on, check wiring between camshaft position sensor connector terminal No. 2 and ECM connector terminal A21 for a short to voltage.
  7. Ensure camshaft position sensor is disconnected. Connect voltmeter between camshaft position sensor terminal No. 2 and ground. If battery voltage is present, reconnect camshaft position sensor connector. Erase DTC. Start and idle engine. If DTC resets, replace camshaft position sensor. If DTC does not reset, DTC was caused by poor terminal contact at camshaft position sensor or ECM connector. If battery voltage is not present, go to next step.
  8. Turn ignition off. Wait about 2 minutes. Connect ohmmeter between camshaft position sensor connector terminal No. 2 and ground. If ohmmeter reads infinite resistance, go to next step. If ohmmeter reads about zero ohms, check wiring between camshaft position sensor connector terminal No. 2 and ECM connector terminal A21 for a short circuit to ground.
  9. Turn ignition off. Disconnect camshaft position sensor. Disconnect ECM connector. Ensure ECM connector terminals are clean and free of oxidation. Reconnect ECM. Turn ignition on. Connect voltmeter between camshaft position sensor connector terminal No. 2 and ground. If voltmeter reads battery voltage, DTC was caused by poor terminal contact at ECM connector. If voltmeter does not read battery voltage, check wiring between camshaft position sensor connector terminal No. 2 and ECM connector terminal A21 for an open circuit.
  10. If fault is intermittent, check camshaft position sensor and ECM connectors for loose connection, contact resistance, or oxidation. Check wiring between camshaft position sensor connector terminal No. 1 and ECM connector terminal A18 for an intermittent open circuit. Check wiring between camshaft position sensor connector terminal No. 2 and ECM connector terminal A21 for an intermittent open circuit, short circuit to ground, or short circuit to voltage. Also check wiring between camshaft position sensor connector terminal No. 3 and ECM connector terminal A36 for an intermittent open circuit.

DTC 315: CANISTER PURGE (CP) SYSTEM

  1. Start and run engine at idle. Remove hose between CP valve and intake manifold. If vacuum is present, go to next step. If vacuum is not present, check if hose between CP valve and intake manifold is plugged. Repair as necessary.
  2. With engine idling, connect hose between CP valve and intake manifold to CP valve. Disconnect hose between CP valve and EVAP canister from CP valve. Ensure there is no vacuum in EVAP valve when valve is not activated. Using scan tool, go to scrolling values list. Check CP valve value to determine whether valve is activated. If there is vacuum, retest using new CP valve. If there is no vacuum, check CP valve for dirt. Attempt to activate CP valve. Ensure valve is not sticking when it is operated. Check all EVAP canister inlets and outlets. Repair as necessary. If no faults can be found, test system using new CP valve.

DTC 335: FAULT IN WIRING BETWEEN TCM & ECM

  1. Check status message on Volvo Scan Tool (998-8686 ). If status message is PERMANENT FAULT, SIGNAL TOO HIGH or PERMANENT FAULT, SIGNAL TOO LOW, go to next step. If status message is INTERMITTENT FAULT, SIGNAL TOO HIGH or INTERMITTENT FAULT, SIGNAL TOO LOW, go to step 3).
  2. If fault is permanent and signal is too high, check wiring between ECM connector terminal B26 and Transmission Control Module (TCM) terminal B15 for a short circuit to voltage. If fault is permanent and signal is too low, check wiring between ECM connector terminal B26 and TCM terminal B15 for a short circuit to ground.
  3. If fault is intermittent and signal is too high, check wiring between ECM connector terminal B26 and TCM terminal B15 for an intermittent short circuit to voltage or an intermittent open circuit. If fault is intermittent and signal is too low, check wiring between ECM connector terminal B26 and TCM terminal B15 for an intermittent short circuit to ground.

DTC 355: MASS AIRFLOW (MAF) SENSOR FAULTY SIGNAL

  1. Turn ignition on. Using scan tool, read off value of Throttle Position (TP) sensor. At Closed Throttle Position (CTP), voltage should be .2-.6 volt. At Wide Open Throttle (WOT), voltage should be 3.8-4.6 volt. If voltages are to specification, go to next step. If voltages are not to specification, go to step 3).
  2. Turn ignition on. Using scan tool, read off value of TP sensor while throttle slowly opens from closed to wide open. If signal follows throttle position and does not have any interference, go to step 7). If signal does not follow throttle position and has interference, replace TP sensor.
  3. Turn ignition off. Check TP sensor and ECM connectors for poor terminal contact. Reconnect connectors. Turn ignition on. Using scan tool, read off value of TP sensor. At Closed Throttle Position (CTP), voltage should be .2-.6 volt. At Wide Open Throttle (WOT), voltage should be 3.8-4.6 volt. If voltages are to specification, DTC was caused by poor terminal contact. If voltages are not to specification, go to next step.
  4. Turn ignition off. Wait about 2 minutes. Disconnect TP sensor. Connect ohmmeter between TP sensor connector terminal No. 1 and ground. If ohmmeter reads about zero ohms, go to next step. If ohmmeter does not read about zero ohms, check wiring between TP sensor terminal No. 1 and ECM terminal A18 for poor terminal contact. Repair as necessary.
  5. Turn ignition on. Disconnect TP sensor connector. Connect voltmeter between TP sensor connector terminal No. 3 and ground. If voltmeter reads about 5-6 volts, go to next step. If voltmeter does not read about 5-6 volts, check wiring between TP sensor terminal No. 3 and ECM terminal A16. for poor terminal contact. Repair as necessary.
  6. Turn ignition off. Wait about 2 minutes. Disconnect TP sensor. Ensure engine cooling fan is not turning. Connect ohmmeter between TP sensor connector terminal No. 2 and ground. If ohmmeter reads about .4-.8 k/ohms, replace TP sensor. If ohmmeter does not read about .4-.8 k/ohms, check wiring between TP sensor terminal No. 2 and ECM connector A15 for poor terminal contact. Repair as necessary.
  7. Check for air leakage in intake system. Repair as necessary. If air leakage is not present, turn ignition off. Wait about 2 minutes. Disconnect MAF sensor connector. Connect ohmmeter between MAF sensor connector terminal No. 1 and ground. If ohmmeter reads about zero ohms, go to step 9). If ohmmeter does not read about zero ohms, go to next step.
  8. Turn ignition off. Disconnect MAF sensor connector. Check ECM connector for poor terminal contact. Repair as necessary. Reconnect ECM connector. Connect ohmmeter between MAF sensor connector terminal No. 1 and ground. If ohmmeter reads about zero ohms, go to next step. If ohmmeter does not read about zero ohms, check wiring between MAF sensor terminal No. 1 and ECM terminal A3 for poor terminal contact. Repair as necessary.
  9. Turn ignition off. Disconnect MAF sensor. Connect ohmmeter between MAF sensor connector terminal No. 2 and ground. If ohmmeter reads about zero ohms, go to next step. If ohmmeter does not read about zero ohms, check ECM connector for poor terminal contact. Reconnect ECM. Connect ohmmeter between MAF sensor connector terminal No. 2 and ground. If ohmmeter reads about zero ohms, go to next step. If ohmmeter does not read about zero ohms, check wiring between MAF sensor terminal No. 2 and ECM terminal A5 for poor terminal contact. Repair as necessary.
  10. Turn ignition off. Disconnect MAF sensor connector. Turn ignition on. Connect voltmeter between MAF sensor connector terminal No. 3 and ground. If voltmeter reads battery voltage, go to next step. If voltmeter does not read battery voltage, check wiring between MAF sensor connector terminal No. 3 and main relay terminal No. 3 for poor terminal contact. Repair as necessary.
  11. Connect voltmeter between MAF sensor connector terminal No. 4 and ground. If voltmeter reads 0-1 volt, go to next step. If voltmeter does not read 0-1 volt, check wiring between MAF sensor terminal No. 4 and ECM terminal No. 4 for poor terminal contact. Repair as necessary.
  12. Turn ignition off. Reconnect MAF sensor. Install breakout box to ECM connector. Reconnect ECM. Connect voltmeter between breakout box pins No. 4 and 5. Turn ignition on. If voltmeter reads .1-.2 volts, DTC was caused by poor terminal contact at MAF and/or ECM connectors. If voltmeter does not read .1-.2 volts, replace MAF sensor.

DTC 411: THROTTLE POSITION SENSOR SIGNAL

  1. Check status message on Volvo Scan Tool (998-8686 ). If status message is PERMANENT FAULT, SIGNAL TOO HIGH, go to next step. If status message is PERMANENT FAULT, SIGNAL TOO LOW, go to step 9). If status message is INTERMITTENT FAULT, SIGNAL TOO HIGH, go to step 13). If status message is INTERMITTENT FAULT, SIGNAL TOO LOW, go to step 15).
  2. Turn ignition off. Wait about 2 minutes. If engine cooling fan is running, wait for it to switch off. Disconnect TP sensor. Connect ohmmeter between TP sensor connector terminal No. 1 and ground. If ohmmeter reads about zero ohms, go to next step. If ohmmeter does not read about zero ohms, go to step 4).
  3. Turn ignition off. Disconnect TP sensor. Disconnect ECM. Clean ECM connector of oxidation or other contact resistance. Reconnect ECM. Connect an ohmmeter between TP sensor connector terminal No. 1 and ground. If ohmmeter reads about zero ohms, DTC is caused by poor contact at ECM connector. If ohmmeter does not read about zero ohms, check wiring between TP sensor connector terminal No. 1 and ECM connector terminal A18 for an open circuit.
  4. Turn ignition on. Disconnect TP sensor. Connect voltmeter between TP sensor connector terminal No. 2 and ground. If voltmeter reads about 5 volts, go to next step. If voltmeter does not show about 5 volts, check wiring between TP sensor connector terminal No. 2 and ECM connector terminal A15 for a short circuit to voltage.
  5. Turn ignition on. Disconnect TP sensor. Connect voltmeter between TP sensor connector terminal No. 3 and ground. If voltmeter reads about 6 volts, go to step 7). If voltmeter reads about zero volts, go to next step. If voltmeter reads more than about 6 volts, check wiring between TP sensor connector terminal No. 3 and ECM connector terminal A16 for a short circuit to voltage. If wiring is okay, go to step 8).
  6. Turn ignition off. Disconnect TP sensor. Disconnect ECM connector. Ensure ECM connector terminals are clean and tight. Reconnect ECM. Turn ignition on. Connect voltmeter between TP sensor connector terminal No. 3 and ground. If voltmeter reads about 6 volts, DTC was caused by poor contact at ECM connector. If voltmeter does not read about 6 volts, check wiring between TP sensor connector terminal No. 3 and ECM connector terminal A16 for an open circuit.
  7. Turn ignition off. Reconnect TP sensor. Start and run engine at idle. Using Volvo Scan Tool (998-8686 ), read throttle angle. Throttle angle should be zero degrees when engine is at idle, increasing as accelerator is depressed. If reading is okay, source of DTC is poor contact at TP sensor connector. If reading is not okay, retest using new TPsensor.
  8. Turn ignition off. Connect TP sensor. Start and idle engine. Using Volvo Scan Tool (998-8686 ), read throttle angle. Throttle angle should be zero degrees when engine is at idle, increasing as accelerator is depressed. If reading is okay, TP sensor is okay. If reading is not okay, retest using new TP sensor.
  9. If fault is permanent and signal is too low, turn ignition off. Wait about 2 minutes. Disconnect TP sensor. Connect ohmmeter between TP sensor connector terminal No. 2 and ground. If ohmmeter reads .3-.8 k/ohm, go to step 11). If ohmmeter reads less than .3 k/ohm, check wiring between TP sensor connector terminal No. 2 and ECM connector terminal A15 for a short circuit to ground. If ohmmeter reads infinite resistance, go to next step.
  10. Turn ignition off. Disconnect TP sensor. Disconnect ECM connector. Ensure ECM connector terminals are clean and tight. Reconnect ECM connector. Turn ignition on. Connect voltmeter between TP sensor connector No. 2 and ground. If voltmeter reads about 6 volts, DTC is caused by poor contact at ECM connector terminals. If voltmeter does not read about 6 volts, check wiring between TP sensor connector terminal No. 2 and ECM connector terminal A15 for an open circuit.
  11. Turn ignition on. Disconnect TP sensor connector. Connect voltmeter between TP sensor connector terminal No. 3 and ground. If voltmeter reads about 6 volts, go to next step. If voltmeter does not read about 6 volts, check wiring between TP sensor connector terminal No. 3 and ECM connector terminal A16 for a short circuit to ground.
  12. Turn ignition off. Connect TP sensor. Start engine. Using Volvo Scan Tool (998-8686 ), read throttle angle. Throttle angle should be zero degrees at idle, and increase as accelerator pedal is depressed. If reading is okay, source of DTC is poor contact in TP sensor connector. If reading is not okay, retest using new TP sensor.
  13. If fault is intermittent and signal is too high, turn ignition off. Disconnect TP sensor. Turn ignition on. Connect voltmeter between TP sensor connector terminal No. 2 and ground. If voltmeter reads about 5 volts, go to next step. If voltmeter does not read about 5 volts, check wiring between TP sensor connector terminal No. 2 and ECM connector terminal A15 for a short circuit to voltage.
  14. Check TP sensor and ECM sensor connector terminals for loose connection, contact resistance, or oxidation. Check wiring between TP sensor connector terminal No. 3 and ECM connector terminal A16 for an intermittent open circuit or short circuit to voltage.
  15. If fault is intermittent and signal is too low, check TP sensor and ECM sensor connector terminals for loose connection, contact resistance, and oxidation. Check wiring between TP sensor connector terminal No. 3 and ECM connector terminal A16 for an intermittent short circuit to ground. Also check wiring between TP sensor connector terminal No. 1 and ECM connector terminal A18 for an intermittent open circuit or short circuit to ground.

DTC 425: REAR HO2S

  1. Perform a compression check on all cylinders. See ADJUSTMENTS article. Repair as necessary. If compression is okay, go to next step.
  2. Check for air leakage in intake system. Repair as necessary. If there is no air leakage in intake system, check for air leakage in exhaust system. Repair as necessary. If there is no air leakage in exhaust system, check fuel and residual pressure. Repair as necessary. If fuel and residual pressure are okay, retest using new HO2S.

DTC 435: FRONT HO2S TOO SLOW

  1. Perform a compression check on all cylinders. See ADJUSTMENTS article. Repair as necessary. If compression is okay, go to next step.
  2. Check for air leakage in intake system. Repair as necessary. If there is no air leakage in intake system, check for air leakage in exhaust system. Repair as necessary. If there is no air leakage in exhaust system, check fuel and residual pressure. Repair as necessary. If fuel and residual pressure are okay, retest using new front HO2S.

DTC 436: REAR HO2S COMPENSATION

  1. Perform a compression check on all cylinders. See ADJUSTMENTS article. Repair as necessary. If compression is okay, go to next step.
  2. Check for air leakage in intake system. Repair as necessary. If there is no air leakage in intake system, check for air leakage in exhaust system. Repair as necessary. If there is no air leakage in exhaust system, check fuel and residual pressure. Repair as necessary. If fuel and residual pressure are okay, go to next step.
  3. Turn ignition on. Squeeze hose between CP valve and intake manifold with Hose Pliers (115 8957). DTC for EVAP system can be set. Start engine and run at idle until rear HO2S starts operating. Rear HO2S starts operating a short time after rear HO2S preheating starts.
  4. Remove multi-nipple plugs. Using scan tool, voltage at rear sensor should drop to zero. Wait 30 seconds. Reinstall multi-nipple plugs. Voltage at rear HO2S should increase to about .8 volt. If voltage at rear HO2S drops to about zero volts, retest using new front HO2S. If voltage at rear HO2S does not drop to about zero volts, retest using new rear HO2S.

DTC 442: PULSED SECONDARY AIR INJECTION SYSTEM (PAIR) FLOW FAULT

This DTC is always stored with DTC 446 (PAIR valve leakage) or DTC 448 (PAIR pump, flow too low). If scan tool indicates PERMANENT FAULT, LEAKAGE, or INTERMITTENT FAULT, LEAKAGE, go to DTC 446 : PULSED SECONDARY AIR INJECTION SYSTEM (PAIR) PUMP FLOW FAULT. If scan tool indicates PERMANENT FAULT, FLOW TOO LOW, or INTERMITTENT FAULT, FLOW TOO LOW, go to DTC 448 : PULSED SECONDARY AIR INJECTION SYSTEM (PAIR) PUMP FLOW FAULT circuit test.

DTC 443: TWC EFFICIENCY

  1. Perform a compression check on all cylinders. See appropriate ADJUSTMENTS article. Repair as necessary. If compression is okay, go to next step.
  2. Check for air leakage in intake system. Repair as necessary. If there is no air leakage in intake system, check for air leakage in exhaust system. Repair as necessary. If there is no air leakage in exhaust system, check fuel and residual pressure. Repair as necessary. If fuel and residual pressure are okay, retest using new TWC.

DTC 444: ACCELEROMETER SIGNAL

  1. Check status message on Volvo Scan Tool (998-8686 ). If status message reads PERMANENT FAULT, SIGNAL TOO HIGH, go to next step. If status message reads PERMANENT FAULT, SIGNAL TOO LOW, go to step 10). If status message reads INTERMITTENT FAULT, SIGNAL TOO HIGH, go to step 11). If status message reads INTERMITTENT FAULT, SIGNAL TOO LOW, go to step 13).
  2. If PERMANENT FAULT, SIGNAL TOO HIGH is displayed on scan tool, turn ignition off. Disconnect accelerometer connector. Turn ignition on. Connect voltmeter between accelerometer connector terminal No. 1 and ground. If voltmeter reads 5 volts, go to next step. If voltmeter reads less than 5 volts, go to step 6). If voltmeter reads more than 5 volts, ensure accelerometer power lead is connected inside ECM to A/C pressure sensor power leads. A problem in one wire will affect both. Repair as necessary.
  3. Turn ignition off. Disconnect accelerometer connector. Connect an ohmmeter between accelerometer connector terminal No. 2 and ground. If ohmmeter reads zero ohms, go to next step. If ohmmeter does not read zero ohms, disconnect ECM connector. Check ECM connector for poor terminal contact. Repair as necessary. Repeat test. If ohmmeter now reads about zero ohms, problem was poor contact at ECM connector. If ohmmeter does not read about zero ohms, check wiring between accelerometer terminal No. 2 and ECM connector terminal B28 for an open circuit.
  4. Turn ignition on. Ensure accelerometer is disconnected. Connect voltmeter between accelerometer connector terminal No. 3 and ground. If voltmeter reads about 5 volts, go to next step. If voltmeter reads greater than 5 volts, check wiring between accelerometer connector terminal No. 3 and ECM connector terminal B32 for a short circuit to voltage. If voltmeter reads less than 5 volts, turn ignition off. Check ECM connector for poor terminal contact. Repeat test. If voltmeter now reads about 5 volts, problem was poor terminal contact. If voltmeter does not read about 5 volts, check wiring between accelerometer connector terminal No. 3 and ECM connector terminal B32 for an open circuit.
  5. Turn ignition on. Reconnect accelerometer. Erase DTC. Start and idle engine. If DTC reoccurs, replace accelerometer. If DTC does not reoccur, DTC was caused by poor terminal contact at accelerometer connector.
  6. Turn ignition off. Disconnect accelerometer connector. Wait 2 minutes. Connect an ohmmeter between accelerometer connector terminal No. 1 and ground. If ohmmeter reads about .2-1.5 k/ohms, DTC was caused by poor terminal contact at ECM. If ohmmeter reads less than .2-1.5 k/ohms, go to step 8). If ohmmeter reads greater than .2-1.5 k/ohms, go to next step.
  7. Check ECM connector for poor terminal contact. Repair as necessary. Connect ohmmeter between accelerometer connector terminal No. 1 and ground. If ohmmeter reads about .2-1.5 k/ohms, DTC was caused by poor ECM connection. If ohmmeter does not read .2-1.5 k/ohms, check wiring between accelerometer terminal No. 1 and ECM connector terminal B1 for an open circuit. Repair as necessary.
  8. Turn ignition off. Disconnect accelerometer connector. Disconnect A/C pressure sensor connector. Connect an ohmmeter between accelerometer connector terminal No. 1 and ground. If ohmmeter reads .2-1.5 k/ohms, replace A/C pressure sensor. If ohmmeter does not read .2-1.5 k/ohms, go to next step.
  9. Accelerometer power lead is connected inside ECM to A/C pressure sensor power lead. A problem with one lead will affect both. Check wiring between accelerometer terminal No. 1 and ECM connector terminal B1, A/C pressure sensor terminal No. 3 and ECM connector terminal B29. Repair as necessary.
  10. If fault is permanent and signal is too low, turn ignition off. Disconnect accelerometer. Turn ignition on. Connect voltmeter between accelerometer connector terminal No. 3 and ground. If voltmeter reads about 5 volts, retest using new accelerometer. If voltmeter does not read about 5 volts, check wiring between accelerometer connector terminal No. 3 and ECM connector terminal B32 for a short circuit to ground.
  11. If fault is intermittent and signal is too high, check accelerometer and ECM connectors for poor terminal contact. Repair as necessary. Check wiring between accelerometer connector terminal No. 1 and ECM connector terminal B1 for an intermittent open or short circuit to ground. Check wiring between accelerometer connector terminal No. 2 and ECM connector terminal B28 for an intermittent open circuit. Check wiring between accelerometer connector terminal No. 3 and ECM connector terminal B32 for an intermittent short circuit to voltage or intermittent open circuit.
  12. Also check for an intermittent short circuit to ground in wiring between accelerometer terminal No. 1 and ECM connector terminal B1, and between A/C pressure sensor terminal No. 3 and ECM connector terminal B29.
  13. If fault is intermittent and signal is too low, check wiring between accelerometer connector terminal No. 3 and ECM connector terminal B32 for an intermittent short circuit to ground.

DTC 445: PULSED SECONDARY AIR INJECTION SYSTEM (PAIR) PUMP SIGNAL

  1. Check status message on scan tool. If status message is PERMANENT FAULT, SIGNAL TOO HIGH, go to next step. If status message is PERMANENT FAULT, SIGNAL TOO LOW, go step 3). If status message is INTERMITTENT FAULT, SIGNAL TOO HIGH, or INTERMITTENT FAULT, SIGNAL TOO LOW, go to step 9).
  2. Turn ignition off. Disconnect PAIR pump relay connector "A". Turn ignition on. Connect test light between relay connector terminal No. 4 and ground. If test light does not come on, replace PAIR pump relay. If test light comes on, check wire between PAIR pump relay connector terminal No. 4 and ECM connector terminal B38.
  3. If status message is PERMANENT FAULT, SIGNAL TOO LOW, check if DTCs 541 and 447 are present. If these DTCs are not present, go to step 5). If these DTCs are present, turn ignition off. Check fuse No. 3. If fuse is okay, go to next step. If fuse is not okay, check wiring after fuse for a short circuit to ground. Repair as necessary.
  4. Turn ignition on. Ensure fuse No. 3 is removed. Check for battery voltage at fuse terminal. If battery voltage is not present, check for an open circuit in wiring between fuse No. 3 and main relay terminal No. 3. If battery voltage is present, check for an open circuit in wiring between fuse No. 3 and PAIR pump relay terminal No. 2.
  5. Ensure ignition is off. Disconnect PAIR pump relay "A". Turn ignition on. Connect voltmeter between relay connector terminal No. 2 and ground. If battery voltage is present, go to next step. If battery voltage is not present, check for an open circuit in wiring between PAIR pump relay terminal No. 2 and fuse No. 3, and between PAIR pump relay terminal A1 and battery. Repair as necessary.
  6. Ensure ignition is off. Disconnect PAIR pump relay. Connect ohmmeter between relay connector terminal No. 4 and ground. If ohmmeter reads infinite resistance, go to next step. If ohmmeter does not read infinite resistance, check for a short circuit to ground in wiring between PAIR pump relay connector terminal No. 4 and ECM connector terminal B38.
  7. Ensure ignition is off and PAIR pump relay is disconnected. Connect Breakout Box (981-3190 ) to ECM connector. Check all grounds. See I - SYSTEM/COMPONENT TETS article. Connect ohmmeter between breakout box pin No. 38 and relay connector terminal No. 4. If ohmmeter reads zero ohms, go to next step. If ohmmeter does not read zero ohms, check for an open circuit in wiring between PAIR pump relay connector terminal No. 4 and ECM connector terminal B38.
  8. Ensure ECM and PAIR pump relay are connected. Turn ignition on. Using scan tool, activate PAIR pump. If PAIR pump operates, cause of DTC was poor terminal contact at relay. If PAIR pump does not operate, replace PAIR pump relay.
  9. If fault is intermittent and signal is too high, check for intermittent short circuit to voltage in wiring between PAIR pump relay terminal and ECM connector terminal B38. If fault is intermittent and signal is too low, check PAIR pump relay and ECM connectors for poor terminal contact. Repair as necessary. Also, check for an intermittent short or open circuit in wiring between PAIR pump relay and ECM connector terminal B38, and between PAIR pump relay connector terminal No. 2 and main relay. Repair as necessary.

DTC 446: PULSED SECONDARY AIR INJECTION SYSTEM (PAIR) PUMP FLOW FAULT

  1. Check status message on scan tool. If status message is PERMANENT FAULT, go to next step. If status message is INTERMITTENT FAULT, check for air leakage in exhaust system. Also check PAIR pipe for damage and leakage.
  2. Turn ignition off. Carefully disconnect vacuum hose from solenoid valve. Connect vacuum gauge to solenoid valve. Start and idle engine so it reaches normal operating temperature. If vacuum gauge indicates no vacuum, go to next step. If vacuum gauge indicates vacuum, go to step 4).
  3. Disconnect PAIR valve from pipe, leaving hoses in place. Turn ignition on. Using scan tool, activate PAIR pump. If no air escapes from PAIR valve outlet, check for air leakage in intake or exhaust system. Repair as necessary. If air does escape from PAIR valve outlet, replace PAIR valve.
  4. Ensure ignition is off. Disconnect solenoid valve connector. Connect vacuum gauge to solenoid valve. Start and idle engine so it reaches normal operating temperature. If vacuum gauge indicates no vacuum, check for a short circuit to ground in wiring between solenoid valve terminal No. 2 and ECM connector terminal A37. If vacuum gauge indicates vacuum, replace solenoid valve.

DTC 447: PULSED SECONDARY AIR INJECTION SYSTEM (PAIR) SOLENOID VALVE SIGNAL

  1. Check status message on scan tool. If status message is PERMANENT FAULT, SIGNAL TOO HIGH, go to next step. If status message is PERMANENT FAULT, SIGNAL TOO LOW, go to step 3). If status message is PERMANENT FAULT, SIGNAL MISSING, go to step 4). If status message is INTERMITTENT FAULT, SIGNAL TOO HIGH, check wiring between solenoid valve terminal No. 2 and ECM connector terminal A37 for an intermittent short circuit to voltage. If status message is INTERMITTENT FAULT, SIGNAL TOO LOW, check wiring between solenoid valve terminal No. 2 and ECM connector terminal A37 for an intermittent short to ground. If status message is INTERMITTENT FAULT, SIGNAL MISSING, go to step 9).
  2. Turn ignition off. Disconnect solenoid valve connector. Turn ignition on. Connect test light between solenoid valve connector terminal No. 2 and ground. If test light does not come on, replace solenoid valve. If test light comes on, check wiring between solenoid valve connector terminal No. 2 and ECM connector terminal A37 for a short circuit to voltage.
  3. If status message is PERMANENT FAULT, SIGNAL TOO LOW, turn ignition off. Disconnect solenoid valve connector. Check wiring between solenoid valve terminal No. 2 and ECM connector terminal A37 for a short circuit to ground.
  4. If status message is PERMANENT FAULT, SIGNAL MISSING, check for additional DTCs. If DTCs 445 and 541 are present, go to next step. If DTC 445 and 541 are not present, go to step 6).
  5. Turn ignition off. Check fuse No. 3. If fuse is okay, check voltage supply to fuse. Repair as necessary. If fuse is not okay, check wiring from fuse for a short circuit to ground. Repair as necessary.
  6. Ensure ignition is off. Disconnect solenoid valve connector. Turn ignition on. Connect voltmeter between solenoid valve connector terminal No. 1 and ground. If voltmeter reads battery voltage, go to next step. If voltmeter does not read battery voltage, check for an open circuit in wiring between solenoid valve terminal No. 1 and main relay. Repair as necessary.
  7. Ensure ignition is off. Connect ohmmeter between solenoid valve terminals No. 1 and 2. If ohmmeter reads about 30-34 ohms, go to next step. If ohmmeter does not read about 30-34 ohms, replace solenoid valve.
  8. Ensure ignition is off. Connect Breakout Box (981-3190) to ECM connector. Check all grounds. See I - SYSTEM/COMPONENT TETS article. Connect ohmmeter between breakout box pin No. 37 and solenoid valve connector terminal No. 2. If ohmmeter reads about zero ohms, DTC is caused by poor contact in ECM and/or solenoid valve connector. If ohmmeter does not read about zero ohms, check for open circuit in wiring between solenoid valve terminal No. 2 and ECM connector terminal A37.
  9. If status message is INTERMITTENT FAULT, SIGNAL MISSING, check solenoid valve and/or ECM connector terminals for poor terminal contact. Check wiring between solenoid valve terminal No. 1 and main relay terminal No. 3 for an intermittent open circuit. Also check wiring between solenoid valve terminal No. 2 and ECM connector terminal A37 for an intermittent open circuit.

DTC 448: PULSED SECONDARY AIR INJECTION SYSTEM (PAIR) PUMP FLOW FAULT

  1. Check status message on scan tool. If status message is PERMANENT FAULT, FLOW TOO HIGH, go to next step. If status message is PERMANENT FAULT, FLOW TOO LOW, go step 4). If status message is INTERMITTENT FAULT, FLOW TOO HIGH, check exhaust system and PAIR pipe for damage or leakage. Repair as necessary. If status message is INTERMITTENT FAULT, FLOW TOO LOW, go to step 15).
  2. Turn ignition off. Carefully disconnect vacuum hose from solenoid valve. Connect vacuum gauge to solenoid valve. Start and idle engine so it reaches normal operating temperature. Start PAIR pump. If vacuum gauge indicates no vacuum, go to next step. If vacuum gauge indicates vacuum, turn ignition off. Disconnect solenoid valve connector. Connect vacuum gauge to solenoid valve. Start and idle engine so it reaches normal operating temperature. If vacuum gauge indicates no vacuum, check for a short circuit to ground in wiring between solenoid valve terminal No. 2 and ECM connector terminal A37. If vacuum gauge indicates vacuum, replace solenoid valve.
  3. Disconnect PAIR valve from pipe. Leave hoses in place. Turn ignition on. Using scan tool, activate PAIR pump. If no air escapes from PAIR valve outlet, check for air leakage in exhaust system. If air escapes from PAIR valve outlet, replace PAIR valve.
  4. If status message is FLOW TOO LOW, PERMANENT FAULT, turn ignition on. Using scan tool, activate PAIR pump. If a clicking sound is heard from relay and PAIR pump starts, go to step 10). If a clicking sound is not heard from relay and PAIR pump does not start, turn ignition off. Disconnect PAIR pump connector. Connect voltmeter between relay side of PAIR pump connector terminals No. 2 and C2. Turn ignition on. Using scan tool, activate PAIR pump. If voltmeter varies between 0 and 12 volts with a 3-second interval, go to next step. If voltmeter does not vary between 0 and 12 volts with a 3-second interval, go to step 7).
  5. Turn ignition off. Connect ohmmeter between PAIR pump connector terminal No. 1 and ground. If ohmmeter does not read zero ohms, go to next step. If ohmmeter does read zero ohms, replace PAIR pump.
  6. Ensure ignition is off. Disconnect PAIR pump. Check PAIR pump ground for contact resistance or poor terminal contact. Repair as necessary. Connect ohmmeter between PAIR pump connector terminal No. 1 and ground. If ohmmeter reads zero ohms, DTC was caused by poor contact at PAIR pump ground. If ohmmeter does not read zero ohms, check for an open circuit in wiring between PAIR pump connector terminal No. 1 and ground. Repair as necessary.
  7. Turn ignition off. Disconnect PAIR pump relay "A" from relay base. Connect voltmeter between relay base terminal No. 1 and ground. If voltmeter reads battery voltage, go to next step. If voltmeter does not read battery voltage, go to step 9).
  8. Ensure PAIR pump is connected. Disconnect secondary PAIR pump relay. Connect jumper wire between PAIR pump relay base terminals No. 1 and 3. If PAIR pump starts, replace PAIR pump relay. If PAIR pump does not start, check for an open circuit in wiring between PAIR pump relay terminal No. 3 and PAIR pump connector terminal No. 2.
  9. Check fuse No. 6. If fuse is not okay, check wiring after fuse No. 6 for a short circuit to ground. Repair as necessary. If fuse is okay, check voltage supply to fuse. Repair as necessary. If voltage supply is okay, check for an open circuit in wiring between fuse No. 6 and PAIR pump relay terminal No. 1. If voltage supply is not okay, check for an open circuit in wiring between battery and fuse No. 6.
  10. Turn ignition off. Disconnect PAIR valve from pipe, leaving hoses in place. Carefully disconnect vacuum hose from PAIR valve. Connect vacuum pump to PAIR valve. Turn ignition on. Using scan tool, activate PAIR pump. Using vacuum pump, pump up vacuum. If air does not escape from PAIR valve outlet when pump is operating, go to step 14). If air escapes from PAIR valve outlet when pump is operating, go to next step.
  11. Ensure PAIR valve is off. Allow vehicle to cool, then remove exhaust tail pipe. Install Conical Connector (999 5546) with Pressure Regulator (999 5544) to exhaust system. Adjust pressure to about 5.8 psi. Depending upon condition of exhaust system a lower pressure may be necessary. Activate PAIR pump. If air is escaping from PAIR pipe, go to next step. If air is not escaping from PAIR pipe, clean PAIR pipe and manifold connector.
  12. Turn ignition off. Using new gasket, reinstall PAIR valve. Carefully disconnect White hose from solenoid valve. Start and idle engine. If there is vacuum in hose, go to next step. If there is not vacuum in hose, ensure White hose, check valve, and connector in intake manifold are not blocked. Repair as necessary.
  13. Turn ignition off. Disconnect hose between solenoid valve and PAIR valve. If hose is leaking or blocked, repair as necessary. If hose is not leaking or blocked, replace solenoid valve.
  14. Ensure ignition is off. Disconnect PAIR hose from PAIR valve. Turn ignition on. Activate PAIR pump. If air escapes when pump operates, replace PAIR valve. If air does not escape, turn ignition off. Disconnect hose between PAIR pump and PAIR valve. Ensure hose is not blocked or leaking. Ensure hose to PAIR pump is not blocked. If hoses are okay, replace PAIR pump. If hoses are not okay, replace hose.
  15. If status message is INTERMITTENT FAULT, FLOW TOO LOW, check hose between PAIR pump and PAIR valve for pinching or damage. Check vacuum hose with check valve between intake manifold and solenoid valve, and hose between solenoid valve and PAIR valve for pinching and damage. Also check PAIR pump ground terminal and PAIR pump relay power supply terminal for an intermittent open circuit. Repair as necessary.

DTC 451-456, 543, 545 OR 551-556: MISFIRE

  1. Check for other DTCs. If any other DTCs are stored, perform diagnosis for other DTCs first. If no other DTCs are stored, go to next step.
  2. Read other misfiring DTCs. If DTC indicates misfiring has occurred in several cylinders, go to step 14). If misfiring occurred in one cylinder, go to next step.
  3. Check cylinder compression. Check cooling system. See ADJUSTMENTS . If all components are okay, turn ignition off. Disconnect affected ignition coil. Put a new spark plug in ignition coil. Place spark plug against engine. Disconnect all injectors. Operate starter motor. If spark is present, go to step 10). If spark is not present, go to next step.
  4. Ensure ignition is off and injectors are disconnected. Disconnect an ignition coil from a cylinder that is not generating misfire DTCs. Connect the known-good ignition coil wire to the suspect ignition coil. Install a new spark plug in ignition coil. Place spark plug against engine. Operate starter motor. If spark is present at spark plug, replace ignition coil. If spark is not present at ignition coil, go to next step.
  5. Turn ignition off. Reinstall ignition coils. Disconnect connector from affected ignition coil. Start engine. Connect voltmeter between ignition coil connector terminal No. 2 and ground. If voltmeter reads battery voltage, go to next step. If voltmeter does not read battery voltage, check for open circuit in wiring between affected coil terminal No. 2 and ignition relay terminal No. 3. Repair as necessary.
  6. Turn ignition on. Disconnect affected ignition coil connector. Connect voltmeter between ignition coil connector terminal No. 1 and ground. If voltmeter reads zero volts, go to next step. If voltmeter does not read zero volts, check for short circuit to supply voltage in signal wire to affected ignition coil. Repair as necessary.
  7. Ensure ignition is off. Wait about 2 minutes. Disconnect affected ignition coil connector. Connect ohmmeter between ignition coil connector terminal No.1 and ground. If ohmmeter reads infinite resistance, go to next step. If ohmmeter does not read infinite resistance, check for short to ground in ignition coil signal wire. Repair as necessary.
  8. Ensure ignition is off. If DTC 451 or 551 is set, check for an open circuit in wiring between cylinder No. 1 ignition coil terminal No. 1 and ignition discharge module terminal No. 1. If DTC 452 or 552 is set, check for an open circuit in wiring between cylinder No. 2 ignition coil terminal No. 1 and ignition discharge module terminal No. 3. If DTC 453 or 553 is set, check for an open circuit in wiring between cylinder No. 3 ignition coil terminal No. 1 and ignition discharge module terminal No. 6. If DTC 454 or 554 is set, check for an open circuit in wiring between cylinder No. 4 ignition coil terminal No. 1 and ignition discharge module terminal No. 6. If DTC 455 or 555 is set, check for an open circuit in wiring between cylinder No. 5 ignition coil terminal No. 1 and ignition discharge module terminal No. 3. If DTC 456 or 556 is set, check for an open circuit in wiring between cylinder No. 6 ignition coil terminal No. 1 and ignition discharge module terminal No. 1. Repair as necessary. If wiring is okay, go to next step.
  9. Ensure ignition is off. If DTC 451 or 551 is set, check for an open, short to ground, or short circuit to voltage in wiring between ignition discharge module terminal No. 2 and ECM terminal B11. If DTC 452 or 552 is set, check for an open, short to ground, or short circuit to voltage in wiring between ignition discharge module terminal No. 5 and ECM terminal B13. If DTC 453 or 553 is set, check for an open, short to ground, or short circuit to voltage in wiring between ignition discharge module terminal No. 7 and ECM terminal B14. If DTC 454 or 554 is set, check for an open, short to ground, or short circuit to voltage in wiring between ignition discharge module terminal No. 7 and ECM terminal B35. If DTC 455 or 555 is set, check for an open, short to ground, or short circuit to voltage in wiring between ignition discharge module terminal No. 5 and ECM terminal B10. If DTC 456 or 556 is set, check for an open, short to ground, or short circuit to voltage in wiring between ignition discharge module terminal No. 2 and ECM terminal B34. If all wiring is okay, replace Ignition Discharge Module (IDM).
  10. Turn ignition on. Using scan tool, read flywheel adaption status. If value displays complete, go to next step. If value does not display complete, adapt flywheel by driving vehicle in low gear and engine braking so fuel shutoff system occurs. Repeat until flywheel adaption display switches to completed. Fuel shutoff system must operate for a total of 40 seconds before flywheel adaption switches to complete.
  11. Install new spark plugs. Start and idle engine. Using scan tool, read off flywheel values on scan tool for adoption values "B" and "C". If readings are .391 to .387, go to next step. If readings are not .391 to .387, check RPM sensor tip and hole down by flywheel/connecting flange for damage, scratches, and metal particles. If RPM sensor and hole are okay, replace flywheel.
  12. Check wiring between relevant injector and ECM for signs of an intermittent open circuit, short circuit to ground, or intermittent short circuit to voltage. Also check suspect injector connector and ECM connector for poor terminal contact or oxidation. Repair as necessary, then go to next step.
  13. Check for air leakage in intake or exhaust system. Repair as necessary. If no air leakage is present, check fuel and residual pressure. See BASIC TESTING article. Repair as necessary. If fuel and residual pressure are okay, system is operating normally.
  14. If misfiring is occurring in several cylinders, use scan tool and read off misfire DTCs. If DTC applies to cylinders No. 1, 3 and 5, go to next step. If DTC applies to cylinders No. 2, 4 and 6, go to step 17). If DTC applies to other combinations of misfire DTCs, go to step 19).
  15. Ignition coils for cylinders No. 1, 3 and 5 are connected to a common Ignition Discharge Module (IDM). If misfire DTCs are stored for these 3 cylinders, the fault is likely located in IDM or ground terminal. Turn ignition off. Disconnect front IDM connector. Connect ohmmeter between IDM connector terminal No. 4 and ground. If ohmmeter reads about zero ohms, replace IDM. If ohmmeter does not read about zero ohms, go to next step.
  16. Ensure ignition is off. Check IDM connector and ground for poor terminal contact. Repair as necessary. Connect ohmmeter between IDM connector terminal No. 4 and ground. If ohmmeter reads about zero ohms, DTC was caused by poor terminal contact at IDM connector or ground. If ohmmeter does not read about zero ohms, check for open circuit in wiring between IDM and ground.
  17. Ignition coils for cylinders No. 2, 4 and 6 are connected to a common Ignition Discharge Module (IDM). If misfire DTCs are stored for these 3 cylinders the fault is likely located in IDM or ground terminal. Turn ignition off. Disconnect rear IDM connector. Connect ohmmeter between IDM connector terminal No. 4 and ground. If ohmmeter reads about zero ohms, replace IDM. If ohmmeter does not read about zero ohms, go to next step.
  18. Ensure ignition is off. Check IDM connector and ground for poor terminal contact. Repair as necessary. Connect ohmmeter between IDM connector terminal No. 4 and ground. If ohmmeter reads about zero ohms, DTC was caused by poor terminal contact at IDM connector or ground. If ohmmeter does not read about zero ohms, check for open circuit in wiring between IDM and ground.
  19. If various combinations of misfire DTCs are present, remove all spark plugs. Perform a compression check on all cylinders. See ADJUSTMENTS article. Repair as necessary. If compression is okay, connect Pressure Tester (998 5496) to expansion tank. Pump up pressure to about 14.2 psi. Shine flashlight into each cylinder and ensure there is no leakage between cooling system and cylinders. If leakage is present, repair as necessary. If no leakage is present, go to next step.
  20. Ensure ignition is on. Using scan tool, read flywheel adaption. If value reads complete, go to next step. If value does not read complete, adapt flywheel by driving vehicle in low gear and engine braking so fuel shutoff system occurs. Repeat until flywheel adaption display switches to completed. Fuel shutoff system must operate for a total of 40 seconds before flywheel adaption switches to complete.
  21. Install new spark plugs. Start and idle engine. Using scan tool, read flywheel adaption "B" and "C" values. If values are .391-.387 percent, go to next step. If values are not .391-.387 percent, check RPM sensor probe and hole. Check RPM sensor tip and hole down by flywheel/connecting flange for damage, scratches, and metal particles. If RPM sensor and hole are okay, replace flywheel.
  22. Check for an open circuit in wiring between injector terminal No. 1 and main relay terminal No. 3, and between ECM terminal A41 and main relay terminal No. 1. Also check injector, main relay, and ECM terminals for poor terminal contact. Repair as necessary, then go to next step.
  23. Check for an intermittent open circuit, short circuit to ground, or short circuit to voltage in wiring between ECM terminal B19 and fuel pump relay terminal No. 4, fuel pump relay terminal No. 2 and ignition switch terminal No. 15, main relay and fuel pump relay terminal No. 1, fuel pump relay terminal No. 3 and fuel pump terminal No. 1, and fuel pump terminal No. 4 and ground. Also check for poor terminal contact at ECM, fuel pump relay, fuse No. 11, main fuse No. 11, positive battery terminal, and grounds. Repair as necessary, then go to next step.
  24. Check for an intermittent open circuit, short circuit to ground, or short circuit to voltage in wiring between fuel pump relay terminal No. 5 and ignition relay terminal No. 2, ignition relay terminal No. 4 and ground, main relay terminal No. 3 and ignition relay terminal No. 1, and ignition relay terminal No. 3 and ignition coils terminal No. 2. Also check for poor terminal contact at all relevant connectors. Repair as necessary, then go to next step. 25) Check intake system for air leakage. Repair as necessary. Check oil level and correct as necessary.

DTC 513: TEMPERATURE WARNING LEVEL 2

See DTC 432 OR 513: TEMPERATURE WARNING LEVEL 2 circuit test.

DTC 514: ENGINE COOLING FAN HALF SPEED

  1. Using Volvo Scan Tool (998-8686 ), read status message. If message PERMANENT FAULT, SIGNAL TOO HIGH is displayed, go to next step. If PERMANENT FAULT, SIGNAL TOO LOW is displayed, go to step 3). If PERMANENT FAULT, SIGNAL MISSING is displayed, go to step 4). If INTERMITTENT FAULT, SIGNAL TOO HIGH is displayed, go to step 8). If INTERMITTENT FAULT, SIGNAL TOO LOW is displayed, go to step 9). If INTERMITTENT FAULT, SIGNAL MISSING is displayed, go to step 10).
  2. If PERMANENT FAULT, SIGNAL TOO HIGH is displayed, turn ignition off. Disconnect connector "B" from Fan Control (FC) relay. Turn ignition on. Connect voltmeter between FC relay connector "B", terminal No. 1, and ground. If voltmeter reads about 6 volts, retest using new FC relay. If voltmeter does not read about 6 volts, check wiring between FC relay connector "B", terminal No. 1, and ECM connector terminal A7 for a short circuit to voltage.
  3. IF PERMANENT FAULT, SIGNAL TOO LOW is displayed, turn ignition off. Disconnect connector "B" from Fan Control (FC) relay. Connect voltmeter between FC relay connector "B" terminal No. 1 and ground. If voltmeter reads about 6 volts, replace FC relay. If voltmeter does not read about 6 volts, check wiring between FC relay terminal B1 and ECM connector terminal A7 for a short circuit to ground.
  4. If PERMANENT FAULT, SIGNAL MISSING is displayed, turn ignition off. Disconnect connector "A" from FC relay. Connect voltmeter between FC relay connector "A" and ground. If voltmeter reads battery voltage, go to next step. If voltmeter does not read battery voltage, check fuse No. 7. If fuse is okay, check fuse wiring for an open circuit. Repair as necessary.
  5. Turn ignition off. Disconnect FC relay connector "A". Disconnect FC relay connector "B". Turn ignition on. Connect voltmeter between relay connector "B" terminal No. 1 and ground. If voltmeter reads about 6 volts, go to next step. If voltmeter does not read about 6 volts, check ECM connector for good terminal contact. Repair as necessary. Repeat test. If voltage is now correct, DTC was caused by poor terminal contact. If voltage is still not correct, check wiring between FC relay terminal B1 and ECM connector terminal A7 for an open circuit.
  6. Turn ignition on. Connect voltmeter between relay connector "B" terminal No. 2 and ground. If voltmeter reads about 3 volts, go to next step. If voltmeter does not read about 3 volts, check wiring between FC relay connector "B" terminal No. 2 and ECM connector terminal A22 for a short circuit to ground.
  7. Turn ignition off. Ensure connectors "A" and "B" are connected to FC relay. Start engine and run at idle. Using Volvo Scan Tool (998-8686 ), read off status message. If status message is PERMANENT, SIGNAL TOO LOW, retest using new FC relay. If status message is intermittent, source of DTC is poor contact in FC relay and/or ECM connector. Ensure connector terminals are clean and free of oxidation.
  8. If INTERMITTENT FAULT, SIGNAL TOO HIGH is displayed, check wiring between FC relay connector "B", terminal No. 1 , and ECM connector terminal A7 for an intermittent short circuit to voltage.
  9. If INTERMITTENT FAULT, SIGNAL TOO LOW is displayed, check wiring between FC relay connector "B", terminal No. 1 , and ECM connector terminal A7 for an intermittent short circuit to ground.
  10. If INTERMITTENT FAULT, SIGNAL MISSING is displayed, check all connectors for poor terminal contact. Repair as necessary. Also check wiring between FC relay "B" terminal No. 1 and ECM connector terminal A7 for an intermittent open circuit. Check wiring between FC relay "A" terminal No. 1 and starter motor for an intermittent open circuit. Check wiring between FC relay "B" terminal No. 2 and ECM connector terminal A22 for an intermittent short to ground.

DTC 521 OR 522: HO2S PREHEATING

  1. Check status message using Volvo Scan Tool (998-8686 ). If PERMANENT FAULT, SIGNAL TOO HIGH is displayed, go to next step. If PERMANENT FAULT, SIGNAL TOO LOW is displayed, go to step 3). If INTERMITTENT FAULT, SIGNAL TOO HIGH is displayed, go to step 9). If INTERMITTENT FAULT, SIGNAL TOO LOW is displayed, go to step 10).
  2. If PERMANENT FAULT, SIGNAL TOO HIGH is displayed, turn ignition off. Disconnect front HO2S Black connector and/or rear HO2S Gray connector. Turn ignition on. Connect voltmeter between HO2S connector terminal No. 2 and ground. If voltmeter reads about zero volts, retest using new HO2S. If voltmeter does not read about zero volts, check wiring between HO2S connector terminal No. 2 and ECM connector terminal A14 (DTC 521) or terminal A29 (DTC 522) for signs of a short circuit to voltage.
  3. If PERMANENT FAULT, SIGNAL TOO LOW is displayed, check for additional DTCs. If DTCs 447 and 541 are not present, go to next step. If DTCs 447 and 541 are present, check fuse No. 3. Replace as necessary. If fuse No. 3 is okay, check voltage supply to and from fuse. If voltage is present at fuse holder, check for an open circuit in wiring between fuse holder and HO2S connector terminal No. 1. If voltage is not present at fuse holder, check for open circuit in wiring between fuse holder and main relay terminal No. 3. Repair as necessary.
  4. Ensure ignition is off. Disconnect front HO2S Black connector and/or rear HO2S Gray connector. Turn ignition on. Connect voltmeter between HO2S connector terminal No. 1 and ground. If voltmeter reads battery voltage, go to next step. If voltmeter does not read battery voltage, check wiring between HO2S connector terminal No. 1 and main relay connector terminal No. 3 for an open circuit.
  5. Turn ignition on. Disconnect HO2S connector. Connect voltmeter between HO2S connector terminal No. 2 and ground. If voltmeter reads about zero volts, go to next step. If voltmeter does not read about zero volts, check wiring between HO2S connector terminal No. 2 and ECM connector terminal A14 (DTC 521) or terminal A29 (DTC 522) for a short circuit to voltage.
  6. Turn ignition off. Wait about 2 minutes. Disconnect HO2S connector. Disconnect ECM. Connect ohmmeter between HO2S connector terminal No. 2 and ground. If ohmmeter reads infinite resistance, go to next step. If ohmmeter does not read infinite resistance, check wiring between HO2S connector terminal No. 2 and ECM connector terminal A14 (DTC 521) or terminal A29 (DTC 522) for a short circuit to ground.
  7. Turn ignition off. Disconnect HO2S and ECM connectors. Connect Breakout Box (981-3190) to ECM connector. Check all grounds. See I - SYSTEM/COMPONENT TETS article. Connect an ohmmeter between HO2S connector terminal No. 2 and breakout box pin No. 14 (DTC 521) or pin No. 29 (DTC 522). If ohmmeter reads about zero ohms, go to next step. If ohmmeter does not read about zero ohms, check wiring between HO2S connector terminal No. 2 and ECM connector terminal A14 (DTC 521) or terminal A29 (DTC 522) for an open circuit.
  8. Turn ignition off. Reconnect HO2S connector. Disconnect ECM connector. Connect ohmmeter between breakout box pins No. 27 and No. 14 (DTC 521) or No. 29 (DTC 522). If ohmmeter reads 1.5-13 ohms, DTC is caused by poor contact in ECM and/or HO2S connector. If ohmmeter does not read 1.5-13 ohms, retest using new HO2S.
  9. If INTERMITTENT FAULT, SIGNAL TOO HIGH is displayed, check wiring between HO2S connector terminal No. 2 and ECM connector terminal A14 (DTC 521) or terminal A29 (DTC 522) for an intermittent short circuit to voltage.
  10. If INTERMITTENT FAULT, SIGNAL TOO LOW is displayed, check wiring between HO2S connector terminal No. 1 and main relay connector terminal No. 3 for an intermittent open circuit. Check wiring between HO2S connector terminal No. 2 and ECM connector terminal A14 (DTC 521) or terminal A29 (DTC 522) for an intermittent open circuit or short circuit to ground. Also check HO2S and ECM connectors for loose connection, contact resistance, and oxidation.

DTC 534: IGNITION DISCHARGE MODULE (IDM) GROUP "D"

  1. Turn ignition off. Disconnect all injectors. Disconnect ignition coils for cylinders No. 1 and 2. Install new spark plugs in ignition coils. Place spark plugs against engine and operate starter. If spark is present at both coils, go to step 4). If no spark is present at cylinder No. 1, go to next step. If no spark is present on cylinder No. 2, go to step 3).
  2. Ensure ignition is off. Disconnect 7-pin front Ignition Discharge Module (IDM) connector. Turn ignition on. Connect test light between IDM connector terminal No. 2 and ground. If test light does not come on, replace IDM. If test light comes on, check for short circuit to voltage in wiring between IDM terminal No. 2 and ECM connector terminal B11.
  3. Ensure ignition is off. Disconnect 7-pin rear Ignition Discharge Module (IDM) connector. Turn ignition on. Connect test light between IDM connector terminal No. 5 and ground. If test light does not come on, replace IDM. If test light comes on, check for short circuit to voltage in wiring between IDM terminal No. 5 and ECM connector terminal B13.
  4. Turn ignition on. Using scan tool, activate cooling fan high speed. If cooling fan relay operates and cooling fan runs after 3 seconds, go to step 7). If cooling fan relay and cooling fan do not operate, go to next step.
  5. Ensure ignition is off. Disconnect cooling Fan Control (FC) relay connector "B". Turn ignition on. Connect test light between FC relay connector "B" terminal No. 2 and ground. If test light does not come on, go to next step. If test light comes on, check for a short circuit to voltage in wiring between FC relay connector "B" terminal No. 2 and ECM connector terminal A22. Repair as necessary.
  6. Ensure ignition is off. Wait about 2 minutes. Disconnect cooling Fan Control (FC) relay connector "B". Connect ohmmeter between FC relay connector "B" terminal No. 2 and ground. If ohmmeter reads infinite resistance, replace FC relay. If ohmmeter does not read infinite resistance, check for short circuit to ground in wiring between FC relay connector "B" terminal No. 2 and ECM connector terminal A22.
  7. Connect breakout box to ECM connector and check ground connections. See SYSTEM/COMPONENT TESTS article. Connect ECM to breakout box. Turn ignition on. Connect voltmeter between breakout box pins No. 7 and 28. If voltmeter reads 0-2 volts, go to next step. If voltmeter does not read 0-2 volts, check wiring between instrument cluster connector terminal B11 and ECM connector terminal B7 for a short circuit to voltage.
  8. Ensure ignition is off. Wait about 2 minutes. Connect breakout box to ECM connector. Connect ohmmeter between breakout box pins No. 7 and 28. If ohmmeter reads about 25 ohms, go to next step. If ohmmeter does not read about 25 ohms, check for short circuit to ground in wire between instrument cluster connector terminal B11 and ECM connector terminal B7. Repair as necessary.
  9. Connect breakout box to ECM connector and check ground connections. See SYSTEM/COMPONENT TESTS article. Connect ECM to breakout box. Turn ignition on. Connect voltmeter between breakout box pins No. 12 and 28. If voltmeter reads 0-1 volt, go to next step. If ohmmeter does not read 0-1 volt, check for a short circuit to voltage in wiring between ECM connector terminal B12 and Transmission Control Module (TCM) connector terminal B12. Repair as necessary.
  10. Problem is intermittent. Check for an intermittent short circuit to voltage in wiring between IDM connector terminal No. 2 and ECM connector terminal B11, and between IDM connector terminal No. 5 and ECM connector terminal B13. Check for an intermittent short circuit to voltage or ground in wiring between FC relay connector "B" terminal No. 2 and ECM connector terminal A22, and between instrument panel connector terminal B11 and ECM connector terminal B7. Also check for an intermittent short to voltage in wiring between ECM connector terminal B12 and Transmission Control Module (TCM) connector terminal B12. Repair as necessary.

DTC 536: IGNITION DISCHARGE MODULE (IDM) GROUP "E"

  1. Turn ignition on. Using scan tool, activate A/C. If A/C relay switches on and off, go to step 3). If A/C relay does not switch on and off, go to next step.
  2. Ensure ignition is off. Remove A/C relay "F" from relay base. Turn ignition on. Connect voltmeter between relay base terminal No. 4 and ground. If voltmeter reads 2-8 volts, replace A/C relay. If voltmeter does not read 2-8 volts, check for a short circuit to voltage or ground in wiring between A/C relay terminal No. 4 and ECM connector terminal B40.
  3. Ensure ignition is off. Disconnect all injectors. Disconnect ignition coils for cylinders No. 3, 4, 5 and 6. Install new spark plugs in ignition coils. Place spark plugs against engine and operate starter. If spark is present at spark plugs, fault is intermittent. Go to step 8). If spark is not present at cylinder No. 3, go to next step. If spark is not present at cylinder No. 4, go to step 5). If spark is not present at cylinder No. 5, go to step 6). If spark is not present at cylinder No. 6, go to step 7).
  4. Ensure ignition is off. Disconnect front connector from Ignition Discharge Module (IDM). Turn ignition on. Connect test light between IDM connector terminal No. 7 and ground. If test light does not come on, replace IDM. If test light comes on, check for short circuit to voltage in wiring between IDM connector terminal No. 7 and ECM connector terminal B14.
  5. Ensure ignition is off. Disconnect rear connector from Ignition Discharge Module (IDM). Turn ignition on. Connect test light between IDM connector terminal No. 7 and ground. If test light does not come on, replace IDM. If test light comes on, check for short circuit to voltage in wiring between IDM connector terminal No. 7 and ECM connector terminal B35.
  6. Ensure ignition is off. Disconnect front connector from Ignition Discharge Module (IDM). Turn ignition on. Connect test light between IDM connector terminal No. 5 and ground. If test light does not come on, replace IDM. If test light comes on, check for short circuit to voltage in wiring between IDM connector terminal No. 5 and ECM connector terminal B10.
  7. Ensure ignition is off. Disconnect rear connector from Ignition Discharge Module (IDM). Turn ignition on. Connect test light between IDM connector terminal No. 2 and ground. If test light does not come on, replace IDM. If test light comes on, check for short circuit to voltage in wiring between IDM connector terminal No. 2 and ECM connector terminal B34.
  8. If fault is intermittent, check for an intermittent short circuit to voltage in wiring between IDM connector terminal No. 7 and ECM connector terminal B14, between IDM connector terminal No. 5 and ECM connector terminal B10, and between IDM connector terminal No. 7 and ECM connector terminal B34. Also check for an intermittent short circuit to ground or voltage between A/C relay terminal No. 4 and ECM connector terminal B40. Repair as necessary.

DTC 541: CANISTER PURGE VALVE SIGNAL

  1. Check status message on Volvo Scan Tool (998-8686 ). If fault is PERMANENT, SIGNAL TOO HIGH, go to next step. If fault is PERMANENT, SIGNAL TOO LOW, check for a short circuit to ground in wiring between CP valve terminal No. 2 and ECM connector terminal A39. Repair as necessary. If fault is PERMANENT, SIGNAL MISSING, go to step 3). If fault is INTERMITTENT, SIGNAL TOO HIGH, check for short to voltage in wiring between CP valve terminal No. 2 and ECM connector terminal A39. If fault is INTERMITTENT, SIGNAL TOO LOW, check for short to ground in wiring between CP valve terminal No. 2 and ECM connector terminal A39. Repair as necessary. If fault is INTERMITTENT, SIGNAL MISSING, go to step 8).
  2. Turn ignition off. Disconnect CP valve connector. Connect test light between CP valve connector terminal No. 2 and ground. If test light does not come on, replace CP valve. If test light comes on, check wiring between CP valve connector terminal No. 2 and ECM connector terminal A39 for a short circuit to voltage.
  3. Check for presence of other DTCs. If DTCs 445 and 447 are not present, go step 5). If DTCs 445 and 447 are present, check fuse No. 3. Replace fuse as necessary. If fuse is okay, go to next step. If fuse is not okay, check for short circuit to ground in wiring from fuse. Repair as necessary.
  4. Ensure ignition is on. Remove fuse No. 3. Connect voltmeter between fuse No. 3 rear connection and ground. If battery voltage is present, check for an open circuit in wiring between fuse No. 3 and CP valve terminal No. 2. If battery voltage is not present, check for an open circuit in wiring between fuse No. 3 and main relay terminal No. 3. Repair as necessary.
  5. Ensure ignition is off. Disconnect CP valve connector. Turn ignition on. Connect voltmeter between CP valve connector terminal No. 1 and ground. If battery voltage is present, go to next step. If battery voltage is not present, check for open circuit in wiring between CP valve terminal No. 1 and main relay terminal No. 3.
  6. Ensure ignition is off. Connect ohmmeter between CP valve terminals No. 1 and 2. If ohmmeter reads about 22-30 ohms, go to next step. If ohmmeter does not read about 22-30 ohms, replace CP valve.
  7. Ensure ignition is off. Connect breakout box to ECM connector and check ground connections. See SYSTEM/COMPONENT TESTS article. Connect ECM to breakout box. Connect ohmmeter between breakout box pin No. 39 and CP valve connector terminal No. 2. If ohmmeter reads about zero ohms, cause of DTC was poor terminal contact at ECM and/or CP connector. If ohmmeter does not read about zero ohms, check for open circuit in wiring between CP valve terminal No. 2 and ECM connector terminal A39. Repair as necessary.
  8. If fault is INTERMITTENT, SIGNAL MISSING, check CP and/or ECM connector terminals for poor terminal contact. Also check for an intermittent open circuit in wiring between CP valve terminal No. 1 and main relay terminal No. 3, and between CP valve terminal No. 2 and ECM connector terminal A39. Repair as necessary.

DTC 611: FUEL TANK SYSTEM, LARGE LEAK

  1. Check status message on Volvo Scan Tool (998-8686 ). If fault is PERMANENT, LARGE LEAK, perform all procedures in next step. If fault is INTERMITTENT, LARGE LEAK, check for defective components as outlined in next step.
  2. Ensure fuel tank filler cap is on correctly and seal is intact. Check EVAP canister, rollover valve, EVAP canister shut-off valve and fuel tank hoses, and hose connectors. Repair as necessary. If no faults are found, go to next step.
  3. Start and idle engine. Disconnect hose between CP valve and EVAP canister from Canister Purge (CP) valve. Using scan tool, go into scrolling values. Read off CP valve value to determine whether valve is active or not active. If there is vacuum in CP valve when valve is activated, go to step 5). If there is no vacuum, go to next step.
  4. Reconnect hose between CP valve and EVAP canister to Canister Purge (CP) valve. Start and idle engine. Disconnect hose between CP valve and intake manifold from CP valve. If vacuum is present in hose, replace CP valve. If vacuum is not present, check if hose is blocked or disconnected.
  5. Turn ignition off. Reinstall CP valve. Disconnect hose between CP valve and EVAP canister. Start and idle engine. Using scan tool, go into scrolling values list. Read off CP valve value to determine if valve is active or not active. If there is vacuum in CP valve when valve is activated, go to next step. If there is no vacuum, check if hose is blocked or disconnected.
  6. Ensure all EVAP canister inlets and outlets are airtight. If inlets and outlets are airtight, go to next step. If inlets and outlets are not airtight, repair as necessary.
  7. Disconnect hose to fuel tank from EVAP canister. Connect vacuum pump to hose. Operate vacuum pump. If it is not possible to pump up vacuum, go to next step. If it is possible to pump up vacuum, check that rollover valve is airtight. Ensure hose between fuel tank and EVAP canister is airtight. Repair as necessary. NOTE: Following step pressurizes fuel tank. Ensure tank does not contain more than 8 gallons of fuel.
  8. Ensure ignition is off. Connect hose from fuel tank to EVAP canister. Remove EVAP canister shut-off valve from its bracket. Clamp hose between EVAP canister shut-off valve and EVAP canister Carefully disconnect EVAP canister hose from CP valve. Connect Pressure Gauge (999 5646) to hose and Pressure Regulator (999 5544) to pressure gauge. Set pressure at one psi (.07 kg/cm 2 ). Open cock valve on pressure gauge. Let pressure build for 5 minutes, ensuring pressure does not increase beyond maximum 1.4 psi (.09 kg/cm 2 ). Shut off cock valve. Pressure may drop .15-.30 psi (.01-.02 kg/cm 2 ) before stabilizing. Read off pressure. Wait 10 minutes.
  9. If pressure does not stabilize, go to step 11). If pressure stabilizes, disconnect pressure gauge. Reconnect EVAP canister hose. Remove hose clamp from hose between CP valve and intake manifold. Start and idle engine. Using scan tool, read off fuel tank pressure and CP valve value. If fuel tank pressure does not drop when CP valve opens, go to next step. If fuel tank pressure drops when CP valve opens, ensure hose to EVAP canister shut-off valve is airtight. Repair as necessary. If hose and connectors are okay, replace EVAP canister shut-off valve.
  10. Turn ignition off. Remove fuel tank pressure sensor located in front of fuel pump. Check all hoses and nipples for blockage. Repair as necessary. If hoses are okay, replace fuel tank pressure sensor.
  11. Ensure ignition is off. Pressurize fuel tank as outlined in step 8). Spray soapy water on fuel tank, fuel hoses and other components. It may be necessary to lower fuel tank to gain access to hoses and connectors on top of tank. Repair as necessary.

DTC 612: FUEL TANK SYSTEM, SMALL LEAK

  1. Check status message on Volvo Scan Tool (998-8686 ). If fault is PERMANENT, SMALL LEAK, perform all procedures in next step. If fault is INTERMITTENT, SMALL LEAK, check for defective components as outlined in next step.
  2. Ensure fuel tank filler cap is on correctly and seal is intact. Check EVAP canister, rollover valve, EVAP canister shut-off valve and fuel tank hoses, and hose connectors. Repair as necessary. If no faults are found, go to next step.
  3. Start and idle engine. Using scan tool, go into scrolling values. If fuel tank pressure drops when CP valve opens, go to next step. If fuel tank pressure does not drop when CP valve opens, go to step 6). NOTE: Following step pressurizes fuel tank. Ensure tank does not contain more than 8 gallons of fuel.
  4. Ensure ignition is off. Remove EVAP canister shut-off valve from its bracket. Clamp hose between CP valve and intake manifold. Carefully disconnect EVAP canister hose from CP valve. Connect Pressure Gauge (999 5646 ) to hose and Pressure Regulator (999 5544 ) to EVAP canister. Set pressure at one psi (.07 kg/cm 2 ). Open cock valve on pressure gauge. Let pressure build for 5 minutes, ensuring pressure does not increase beyond maximum .15 psi (.010 kg/cm 2 ). Shut off cock valve. Read off pressure after 10 minutes.
  5. If pressure does not stabilize, go to step 7). If pressure stabilizes, check connectors and hose to EVAP canister shut-off valve for airtightness. If components are okay, go to next step. If components are not okay, go to step 7).
  6. Turn ignition off. Remove fuel tank pressure sensor located in front of fuel pump. Check all hoses and nipples for blockage. Repair as necessary. If hoses are okay, replace fuel tank pressure sensor.
  7. Ensure ignition is off. Pressurize fuel tank as outlined in step 4). Spray soapy water on fuel tank, fuel hoses and other components. It may be necessary to lower fuel tank to gain access to hoses and connectors on top of tank. Repair as necessary.

DTC 614: EVAP CANISTER SHUT-OFF VALVE FLOW FAULT

  1. Check status message on Volvo Scan Tool (998-8686 ). If fault is PERMANENT, FLOW FAULT, go to next step. If fault is INTERMITTENT, FLOW FAULT, check all components for blockage, kinks, dirt or other deposits. Repair as necessary.
  2. Start and idle engine. Open fuel filler cap. Using scan tool, read off fuel tank pressure value. If fuel tank pressure value is greater than-.15 psi (-.010 kg/cm 2 ), go to next step. If fuel tank pressure value is not greater than -.15 psi (-.010 kg/cm 2 ), remove fuel tank and replace fuel tank pressure sensor. Fuel tank pressure sensor is located on top of fuel tank in front of fuel pump.
  3. Disconnect hose between CP valve and EVAP canister from CP valve. Start and idle engine. Using scan tool, check whether EVAP valve is activated. If there is no vacuum in EVAP valve when valve is not activated, go to next step. If there is vacuum when valve is not activated, replace CP valve.
  4. Turn ignition off. Ensure hose between EVAP canister and EVAP canister shut-off valve is not pinched or kinked. If hose appears okay, carefully disconnect it from EVAP canister and EVAP shut-off valve and check hose for blockage. Replace hose as necessary. If hose is okay, go to next step.
  5. Ensure ignition is off. Carefully disconnect hose to EVAP canister shut-off valve. Disconnect end of hose from EVAP canister. If EVAP canister shut-off valve connector in EVAP canister is blocked, replace EVAP canister. If EVAP canister shut-off valve connector in EVAP canister is not blocked, repeat step 3).

DTC 616: EVAP CANISTER SHUT-OFF VALVE SIGNAL

  1. Check status message on Volvo Scan Tool (998-8686 ). If fault is PERMANENT, SIGNAL TOO HIGH, go to next step. If fault is PERMANENT, SIGNAL TOO LOW, check for short circuit to ground in wiring between EVAP canister shut-off valve terminal No. 2 and ECM connector terminal B19. If fault is PERMANENT, SIGNAL MISSING, go to step 3). If fault is INTERMITTENT, SIGNAL TOO HIGH, check wiring for a short to voltage between EVAP canister shut-off valve connector terminal No. 2 and ECM connector terminal B19. If fault is INTERMITTENT, SIGNAL TOO LOW, check wiring for a short to ground between EVAP canister shut-off valve terminal No. 2 and ECM connector terminal B19. If fault is INTERMITTENT, SIGNAL MISSING, go to step 6).
  2. Turn ignition off. Disconnect EVAP canister shut-off valve connector. Turn ignition on. Connect test light between shut-off valve connector terminal No. 2 and ground. If test light does not come on, replace EVAP canister shut-off valve. If test light comes on, check for short circuit to voltage in wiring between EVAP canister shut-off valve connector terminal No. 2 and ECM connector terminal B19.
  3. Turn ignition off. Disconnect EVAP canister shut-off valve connector. Turn ignition on. Measure voltage between EVAP shut-off valve connector terminal No. 1 and ground. If battery voltage is present, go to next step. If battery voltage is not present, check wiring for an open circuit between EVAP shut-off valve terminal No. 1 and main relay.
  4. Ensure ignition is off. Connect ohmmeter between EVAP canister shut-off valve terminals No. 1 and 2. If ohmmeter reads 14-20 ohms, go to next step. If ohmmeter does not read 14-20 ohms, replace EVAP canister shut-off valve.
  5. Connect breakout box to ECM connector. Connect ohmmeter between breakout box pin No. 19 and EVAP canister shut-off valve connector terminal No. 2. If ohmmeter reads about zero ohms, DTC was caused by poor terminal contact at ECM or EVAP canister shut-off valve. Repair as necessary. If ohmmeter does not read about zero ohms, check for open circuit in wiring between EVAP canister shut-off valve terminal No. 2 and ECM connector terminal B19.
  6. Check EVAP canister shut-off valve and/or ECM connectors for loose connections, contact resistance or oxidation. Check wiring for an intermittent open circuit between EVAP canister shut-off valve terminal No. 1 and main relay terminal No. 3. Also check wiring for an intermittent open circuit between EVAP canister shut-off valve terminal No. 2 and ECM connector terminal B19.

DTC 621: FUEL TANK PRESSURE SENSOR SIGNAL

  1. If fault is permanent, signal too high, go to next step. If fault is permanent, signal too low, go to step 7). If fault is permanent, signal sporadic, go to step 14). If fault is intermittent, signal too high, go tostep 18). If fault is intermittent, signal too low, go to step 19). If fault is intermittent, signal sporadic, go to step 20).
  2. Turn ignition off. Wait about 2 minutes. Disconnect fuel tank pressure sensor. Connect ohmmeter between fuel tank pressure sensor connector terminal No. 2 and ground. If ohmmeter reads about zero ohms, go to step 4). If ohmmeter does not read about zero ohms, go to next step.
  3. Ensure ignition is off and fuel tank pressure sensor is disconnected. Check all connectors and wiring between fuel tank pressure sensor and ECM for an open circuit or poor terminal contact. Connect ohmmeter between fuel tank pressure sensor connector terminal No. 2 and ground. If about zero ohms are present, problem was caused by poor terminal contact. If about zero ohms are not present, check wiring between fuel tank pressure sensor terminal No. 2 and ECM connector terminal A18 for an open circuit. Repair as necessary.
  4. Turn ignition on. Disconnect fuel tank pressure sensor connector. Measure voltage between fuel tank pressure sensor connector terminal No. 3 and ground. If voltage is less than 5 volts, go to next step. If voltage is greater than 6 volts, check all wiring and connectors between fuel tank pressure sensor and ECM for a short circuit to voltage. If voltage is 5-6 volts, go to step 6).
  5. Turn ignition off. Disconnect fuel tank pressure sensor connector. Check ECM and other connectors between fuel tank pressure sensor and ECM for an open circuit or poor terminal contact. Repair as necessary. Reconnect all connectors. Turn ignition on. Using voltmeter, backprobe between fuel tank pressure sensor connector terminal No. 3 and ground. If about 5 volts are present, system is okay. If about 5 volts are not present, repair open circuit in wiring between fuel tank pressure sensor and ECM terminal B31. See WIRING DIAGRAMS .
  6. Turn ignition off. Ensure fuel tank pressure sensor is connected. Start and idle engine for several minutes. Using scan tool, check DTC status message. If an alternative permanent fault is present, replace fuel tank pressure sensor. If alternative intermittent fault is present, DTC was caused by loose connection in fuel tank pressure sensor. Repair as necessary.
  7. If fault is permanent, signal too low, turn ignition off. Wait about 2 minutes. Disconnect fuel tank pressure sensor. Connect ohmmeter between fuel tank pressure sensor connector terminal No. 1 and ground. If ohmmeter reads about .2-1.5 k/ohms, go to step 13). If ohmmeter reads less than .2 k/ohms, go to next step. If ohmmeter reads greater than 1.5 k/ohms, go to step 12).
  8. Ensure ignition is off. Disconnect fuel tank pressure sensor. Disconnect accelerometer. Connect ohmmeter between fuel tank pressure sensor connector terminal No. 1 and ground. If ohmmeter reads about .2-1.5 k/ohms, replace accelerometer. If ohmmeter does not read about .2-1.5 k/ohms, go to next step.
  9. Ensure ignition is off. Disconnect fuel tank pressure sensor, accelerometer, and A/C pressure sensor connectors. Connect ohmmeter between fuel tank pressure sensor connector terminal No. 1 and ground. If ohmmeter reads .2-1.5 k/ohms, replace A/C pressure sensor. If ohmmeter does not read .2-1.5 k/ohms, go to next step.
  10. Ensure ignition is off and fuel tank pressure sensor, accelerometer, A/C pressure sensor, and atmospheric pressure sensor connectors are disconnected. Connect ohmmeter between fuel tank pressure sensor connector terminal No. 3 and ground. If ohmmeter reads .2-1.5 k/ohms, replace atmospheric pressure sensor. If ohmmeter does not read .2-1.5 k/ohms, go to next step.
  11. Fuel tank pressure sensor power lead is connected inside ECM to accelerometer and A/C pressure sensor power leads. If a problem occurs in any power lead all 3 components will be affected. Check for an open circuit or short to ground in wiring between accelerometer terminal No. 1 and ECM terminal B1, A/C pressure sensor terminal No. 3 and ECM terminal B29, and fuel tank pressure sensor terminal No. 1 and ECM terminal B15. Repair as necessary.
  12. Ensure ignition is off. Disconnect fuel tank pressure sensor connector. Check ECM connector for poor terminal contact. Repair as necessary. Reconnect ECM connector. Connect ohmmeter between fuel tank pressure sensor connector terminal No. 1 and ground. If ohmmeter reads about .2-1.5 k/ohms, problem was caused by poor terminal contact. If ohmmeter does not read about .2-1.5 k/ohms, check wiring between fuel tank pressure sensor terminal No. 1 and ECM connector terminal B15 for an open circuit. Repair as necessary.
  13. Turn ignition off. Disconnect fuel tank pressure sensor. Turn ignition on. Connect voltmeter between fuel tank pressure sensor connector terminal No. 3 (ECM side) and ground. If voltmeter reads about 5-6 volts, replace fuel tank pressure sensor. If voltmeter does not read about 5-6 volts, check wiring between fuel tank pressure sensor terminal No. 3 and ECM connector B31 for an open circuit.
  14. If fault is permanent, signal sporadic, turn ignition off. Check fuel tank pressure sensor, ECM, and all other tank pressure sensor connectors for poor terminal contact. Repair as necessary. Read off DTCs. If DTC 621 is stored with intermittent fault status, DTC was caused by poor terminal contact. If DTC is stored with permanent status, go to next step.
  15. Check all fuel tank pressure sensor wiring and connectors for open circuits or poor terminal contact. If wiring and connectors are okay, note that fuel tank pressure sensor power lead is connected inside ECM to A/C pressure sensor and accelerometer power leads. If a problem occurs in any lead all 3 components will be affected. If DTC 621 continues to have permanent fault status, go to next step.
  16. Ensure ignition is off. Ensure fuel tank pressure sensor is connected. Disconnect A/C pressure sensor. Start and idle engine for 5 minutes. Read off DTCs. If DTC 621 is stored with intermittent fault status, replace A/C pressure sensor. If DTC 621 is stored with permanent fault status, go to next step.
  17. Reconnect A/C pressure sensor connector. Disconnect accelerometer connector. Start and idle engine for 5 minutes. Read off DTCs. If DTC 621 is stored with intermittent fault status, replace accelerometer. If DTC 621 is stored with permanent fault status, replace fuel tank pressure sensor.
  18. If fault is intermittent, signal too high, check fuel tank pressure sensor and ECM connectors for poor terminal contact. Check wiring between fuel tank pressure sensor connector terminal No. 3 and ECM terminal B31 for an intermittent open circuit or short circuit to voltage. Also check wiring between fuel tank pressure sensor terminal No. 2 and ECM terminal A18 for an intermittent open circuit. Repair as necessary.
  19. If fault is intermittent, signal too low, check fuel tank pressure sensor and ECM connectors for poor terminal contact. Repair as necessary. If terminal contact is okay, check for an intermittent short circuit to ground in wiring between fuel tank pressure sensor terminal No. 3 and ECM terminal B31, between fuel tank pressure sensor terminal No. 1 and ECM terminal B15, between accelerometer terminal No. 1 and ECM terminal B1, and between A/C pressure sensor terminal No. 3 and ECM terminal B29. Repair as necessary.
  20. If fault is intermittent, signal sporadic, check fuel tank pressure sensor and ECM connectors for poor terminal contact. Repair as necessary. If terminal contact is okay, check for an intermittent open circuit, or short circuit to ground or voltage in wiring between fuel tank pressure sensor terminal No. 1 and ECM terminal B15, between fuel tank pressure sensor terminal No. 3 and ECM terminal B31, and between fuel tank pressure sensor terminal No. 2 and ECM terminal A18. Repair as necessary.
  21. If wiring is okay, note that fuel tank pressure sensor power lead is connected inside ECM to A/C pressure sensor and accelerometer power leads. If anything happens to any of these power leads all 3 components will be affected. Check for an intermittent short circuit to voltage or ground in wiring between A/C pressure sensor terminal No. 3 and ECM terminal B29, and between accelerometer terminal No. 1 and ECM terminal B1.

DTC 666: DTC IN TRANSMISSION CONTROL MODULE (TCM)

This DTC indicates whether there are one or more emission related DTCs stored in TCM. See appropriate VOLVO AW40 SERIES TESTING & DIAGNOSIS article in AUTOMATIC TRANSMISSIONS section.

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