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Engine Controls - Tests W/codes: Diagnosis Volvo V70 I

Testing & Diagnostics 3 illustrations ~32629 words

SELF-DIAGNOSTIC SYSTEM

Volvo C70, S70 and V70 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 S90 and V90 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 Heated 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 OBD-II Data Link Connector (DLC). DLC is located in center console in front of gear shift lever. see scheme 1

ON-BOARD DIAGNOSTICS (OBD-II)

Federal Test Procedure (FTP) sets maximum allowable emission standards. A Malfunction Indicator Light (MIL) must illuminate if a system or component either fails or deteriorates to a point where the vehicle emissions could increase to more than 1 1/2 times FTP standards. Self-diagnostic system is used to provide vehicle with an on-board diagnostic system which is capable of continuously monitoring efficiency of emission control system, and improving diagnosis and repair when system failures occur. Engine Control Module (ECM) monitors engine operation and contains a self-diagnostic system which stores Diagnostic Trouble Codes (DTC) and complies to On-Board Diagnostics Generation II (OBD-II) standards.

If malfunction does not reoccur in 3 consecutive trips, MIL goes off, but DTCs remain recorded in ECM memory. DTCs may only be retrieved using an On-Board Diagnostic-II (OBD-II) scan tool that complies with SAE standard J-1978 or Volvo hand-held tester connected to Data Link Connector (DLC). see scheme 1 Scan tool also provides freeze frame data and can be used to clear DTCs.

To properly diagnose vehicle, vehicle manufacturer recommends use of Volvo Scan Tool. Generic scan tools may not be capable of performing all diagnostic functions. See DIAGNOSTIC FUNCTIONS . All voltage tests should be performed with a Digital Volt-DVOM (DVOM) with a minimum 10-megaohm input impedance, unless specifically stated differently in testing procedures. Ensure ignition switch is in OFF position when performing resistance tests.

RE-TESTING PARTS OF TRIP CYCLE USING VOLVO SYSTEM TESTER (VST)

Note. The following information is from Volvo technical service bulletin No. 0059, Section 2, Group 23, dated July, 2002.

Note. Engine must have been left running. If engine has been shut off before completion of TRIP cycle, entire cycle must be repeated. Engine idle and drive times may be slightly longer than given time, but must be NO LESS than set amount.

  1. Using VST, access DIAGNOSTIC CHECK menu and press Enter at TRIP/READINESS window. This will display a list of all EFI codes. Note each code that is displayed as NOT TESTED. Proceed as follows. EFI-233, Adaptive Idle Air Trim. Idle engine for 60 seconds. Rev engine above 1500 RPM for a few seconds and let idle for another 60 seconds. Repeat until status changes to TESTED. If no other systems display NOT TESTED, TRIP cycle is complete. EFI-425/436, Rear Oxygen Sensor. Test drive vehicle and reach at least 45 mph. Drive for 5 minutes with engine speed of 1800-2200 RPM. Repeat until status changes to TESTED. If no other systems display NOT TESTED, TRIP cycle is complete. EFI-435, Front Heated Oxygen Sensor. Drive vehicle with engine speed of 2200-2800 RPM and load of 1.1-1.8 ms (LOAD-TL). Drive for 2 minutes at engine speed of 1800-2200 RPM. Test drive vehicle and accelerate quickly to engine speed of 3000-3500 RPM. Maintain engine speed for 30 seconds. Reduce engine speed to 1800-2200 RPM and maintain engine speed for 2 minutes. Test drive vehicle and accelerate quickly to engine speed of 3000-3500 RPM and maintain engine speed for 30 seconds. Reduce engine speed to 2300-2500 RPM and maintain engine speed for 2 minutes. Repeat process until status changes to TESTED. If no other systems display NOT TESTED, TRIP cycle is complete. EFI-611/612, Fuel Tank System. Run quick test using VST. Select ACTIVATION menu. Select ACTIVATE DIAG. Select LEAKAGE DIAGNOSIS. Status will change to TESTED if system is functioning properly. If no other systems display NOT TESTED, TRIP cycle is complete. EFI-442/445-448, PAIR System. Go to step Run quick test using VST. Select ACTIVATION menu. Select ACTIVATE DIAG. Select SASDIAGNOSIS. Status will change to TESTED if system is functioning properly. If no other systems display NOT TESTED, TRIP cycle is complete. Go to next step when all diagnostics are complete using VST.
  2. TRIP cycle is complete when all systems are checked. Some readiness codes may display as INCOMPLETE. This will not affect function of OBD-II system. This can be disregarded.

CONNECTING VOLVO TEST BOX (981 3190)

Volvo Test Box (981 3190) is connected simultaneously to Engine Control Module (ECM) wiring harness and ECM. Motronic control system remains fully functional when the test box is connected (e.g. for measuring signals while engine is running). Whether ECM needs to be connected to test box or not is described in respective test procedures.

CONNECTING TEST BOX

  1. Turn ignition off.
  2. Wait three minutes before continuing. Locate ECM in control module box at right front of engine compartment. (Scheme 21) Being careful not to damage ECM pins and connectors, lift up on release lever and pull ECM up and out.
  3. Connect Volvo test box (981 3190) or equivalent, to ECM harness connector in control module box. (Scheme 22) Connect Adapter (951 1351) to test box harness connector "A" or "B" as instructed in diagnostic testing procedure. Continue with diagnostic testing as directed in testing procedure.
  4. After reinstalling ECM, check DTC memory and erase, if necessary. See «RETRIEVING & ERASING DTCs»(ref-15336-S41120021042000122900000) under SELF-DIAGNOSTIC SYSTEM.

Scheme 21

Scheme 21
Scheme 21

Scheme 22

Scheme 22
Scheme 22

Diagnosis

  1. If signal from MAF sensor is less than 0.2 volts or more 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. NOTE: Wait approximately 245 seconds (4 minutes) before disconnecting MAF sensor if vehicle is equipped with an immobilizer.
  4. Turn ignition off. Wait approximately 150 seconds (2.5 minutes) and disconnect MAF sensor. Connect DVOM between MAF sensor connector terminal No. 1 and ground. If DVOM reads approximately zero ohms, go to next step. If DVOM does not indicate approximately zero ohms, check ECM connector for good terminal contact. Repair as necessary. Repeat test. If ECM connector terminal contact is okay, and/or DVOM still does not read approximately zero ohms, check wiring between MAF sensor connector terminal No. 1 and ECM connector terminal A3 for an open circuit.
  5. Turn ignition off. Ensure MAF sensor is disconnected. Connect DVOM between MAF sensor connector terminal No. 2 and ground. If DVOM indicates approximately zero ohms, go to step 7 . If DVOM does not indicate approximately zero ohms, go to next step.
  6. Turn ignition off. Ensure MAF sensor is disconnected. Ensure ECM connector terminals are not oxidized and make good contact. Reconnect ECM. Connect DVOM between MAF sensor connector terminal No. 2 and ground. If DVOM indicates approximately zero ohms, go to next step. If DVOM does not indicate approximately zero ohms, check wiring between MAF sensor connector terminal No. 2 and ECM connector terminal A5 for an open circuit.
  7. Turn ignition on. Ensure MAF sensor is disconnected. Measure voltage between MAF sensor connector terminal No. 4 and ground. If voltage is 0-1 volt, go to next step. If voltage is not 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. Measure voltage between MAF sensor connector terminals No. 2 and 4. If voltage is approximately .1-.2 volt, DTC is caused by poor contact at MAF sensor and/or ECM connectors. If voltage is not approximately .1-.2 volt, replace MAF sensor.
  9. Turn ignition 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. Measure voltage 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. NOTE: Wait approximately 245 seconds (4 minutes) if vehicle is equipped with an immobilizer.
  10. Turn ignition off. Wait 150 seconds, then disconnect MAF sensor. Connect DVOM between MAF sensor connector terminal No. 4 and ground. If DVOM indicates 9-11 k/ohms, go to next step. If DVOM shows approximately zero ohms, check wiring between MAF sensor connector terminal No. 4 and ECM connector terminal A4 for a short to ground. If DVOM 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. Measure voltage between MAF sensor connector terminals No. 4 and 2. If voltage is .1-.2 volt, check for poor contact at MAF sensor and/or ECM connectors. If voltage is not .1-.2 volt, test system using a known good MAF sensor.

Note. Before performing following test, disconnect engine cooling fan relay connector "A". DTC 514 (engine cooling fan half speed) signal will be set. After testing, reattach connector.

Fault Symptoms

  1. None
  1. Turn ignition on. Using scan tool, read Throttle Position (TP) sensor value. At Closed Throttle Position (CTP), voltage should be between 0.2-0.6 volts. At Wide Open Throttle (WOT), voltage should be 3.8-4.6 volts. If voltage is to specification, go to next step. If voltage is not to specification, go to step 3 .
  2. Turn ignition on. Using scan tool, note values 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 or has interference, replace TP.
  3. Turn ignition off. Check TP and ECM connector terminals for good terminal contact. Repair as necessary. If terminal contact is okay, reconnect connectors. Turn ignition on. Using scan tool, read TP sensor value. At Closed Throttle Position (CTP), voltage should be between 0.2-0.6 volts. At Wide Open Throttle (WOT), voltage should be 3.8-4.6 volts. If voltage is to specification, cause of DTC was poor terminal contact. If voltage is not to specification, go to next step.
  4. Turn ignition off. Wait approximately 2 minutes. Disconnect TP sensor connector. Ensure cooling fan is not running. Connect DVOM between TP sensor connector terminal No. 1 and ground. If DVOM reads approximately zero ohms, go to next step. If DVOM does not read approximately zero ohms, check wiring between TP sensor terminal No. 1 and ECM connector terminal A18 for poor terminal contact. Repair as necessary.
  5. Turn ignition on. Disconnect TP sensor connector. Measure voltage between TP sensor connector terminal No. 3 and ground. If voltage is approximately 5 volts, go to next step. If voltage is not approximately 5 volts, check wiring between TP sensor connector terminal No. 3 and ECM connector terminal A16 for poor terminal contact. Repair as necessary.
  6. Turn ignition off. Wait approximately 2 minutes. Disconnect TP sensor connector. Ensure cooling fan is not running. Connect DVOM between TP sensor connector terminal No. 2 and ground. If DVOM reads approximately 400-800 ohms, replace TP sensor. If DVOM does not read approximately 400-800 ohms, check wiring between TP sensor terminal No. 2 and ECM connector terminal A15 for poor terminal contact. Repair as necessary.
  7. Check intake system for air leaks. Repair as necessary. If no air leaks are present, turn ignition off. Wait approximately 2 minutes. Disconnect Mass Airflow (MAF) sensor. Connect DVOM between MAF sensor connector terminal No. 1 and ground. If DVOM reads approximately zero ohms, go to step 10 . If DVOM does not read approximately zero ohms, go to next step.
  8. Turn ignition off. Ensure MAF sensor connector is disconnected. Check ECM connector terminals for good terminal contact. Repair as necessary. Reconnect ECM connector. Connect DVOM between MAF sensor connector terminal No. 1 and ground. If DVOM reads approximately zero ohms, go to next step. If DVOM does not read approximately zero ohms, check wiring between MAF sensor connector terminal No. 1 and ECM connector terminal A3 for an open circuit. Repair as necessary.
  9. Turn ignition off. Ensure MAF sensor connector is disconnected. Connect DVOM between MAF sensor connector terminal No. 2 and ground. If DVOM reads approximately zero ohms, go to step 11 . If DVOM does not read approximately zero ohms, go to next step.
  10. Turn ignition off. Ensure MAF sensor connector is disconnected. Check ECM connector terminals for poor terminal contact. Repair as necessary. Reconnect ECM connector. Connect DVOM between MAF sensor connector terminal No. 2 and ground. If DVOM reads approximately zero ohms, go to next step. If DVOM does not read approximately zero ohms, check wiring between MAF sensor connector terminal No. 2 and ECM connector terminal A5 for poor terminal contact. Repair as necessary.
  11. Turn ignition off. Ensure MAF sensor connector is disconnected. Turn ignition on. Measure voltage 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 terminal No. 3 and main relay terminal No. 3 for poor terminal contact. Repair as necessary.
  12. Turn ignition on. Ensure MAF sensor connector is disconnected. Measure voltage between MAF sensor connector terminal No. 4 and ground. If voltage is 0-1 volt, go to next step. If voltage is not 0-1 volt, check wiring between MAF sensor connector terminal No. 4 and ECM connector terminal A4 for an open circuit. Repair as necessary.
  13. Turn ignition off. Ensure MAF sensor is connected. Connect test box and check ECM ground connections for poor terminal contact. Connect test box to Transmission Control Module (TCM). Measure voltage between test box pins No. 4 and 5. If voltage is 0.1-0.2 volts, DTC was caused by poor terminal contact at MAF and/or ECM connection. Repair as necessary. If voltage is not 0.1-0.2 volts, replace MAF.
  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 permanent, and signal is sporadic, go to step 19 . If fault is intermittent, and signal is too high, go to step 25 . If fault is intermittent, and signal is too low, go to step 26 . If fault is intermittent, and signal is sporadic, go to step 27 .
  2. If fault is permanent, and signal is too high, turn ignition off. Wait approximately 150 seconds (2.5 minutes). Disconnect Lavender colored atmospheric pressure sensor. Connect DVOM between atmospheric pressure sensor connector terminal No. 2 and ground. If DVOM reads approximately zero ohms, go to step 4 . If DVOM does not read approximately zero ohms, go to next step.
  3. Turn ignition off. Ensure atmospheric pressure sensor is disconnected. Check ECM connector terminals for poor terminal contact. Repair as necessary. Reconnect ECM. Connect DVOM between atmospheric pressure sensor connector terminal No. 2 and ground. If DVOM reads approximately zero ohms, go to next step. If DVOM does not read approximately zero ohms, check wiring between atmospheric pressure sensor terminal No. 2 and ECM connector terminal No. 28 for an open circuit.
  4. Turn ignition on. Ensure atmospheric pressure sensor is disconnected. Connect test light between atmospheric pressure senor 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 atmospheric pressure sensor terminal No. 3 and ECM connector terminal B22 for a short to voltage. Repair as necessary.
  5. Ignition off. Ensure atmospheric pressure sensor is disconnected. Measure resistance between atmospheric pressure sensor connector terminal 3 and ground. Reading should be less than approximately 10 k/ohms. If resistance is OK, go to next step. If not, check wiring between atmospheric pressure sensor terminal No. 3 and ECM connector terminal B22 for an open circuit. Repair as necessary.
  6. Turn ignition on. Ensure atmospheric pressure sensor is disconnected. Measure voltage between atmospheric pressure sensor connector terminal No. 1 and ground. If voltage is not approximately 5 volts, go to next step. If voltage is approximately 5 volts, replace atmospheric pressure sensor.
  7. Turn ignition off. Disconnect A/C pressure sensor, fuel tank pressure sensor, accelerometer, and atmospheric pressure sensor connectors. Turn ignition on. Measure voltage between atmospheric pressure sensor connector terminal No. 1 and ground. If voltage is approximately 5 volts, go to step 8 . If voltage is not approximately 5 volts, go to next step.
  8. Atmospheric pressure sensor voltage supply is connected inside ECM to A/C pressure sensor, fuel tank pressure sensor, and accelerometer voltage supply. If anything happens to any of these wires all 4 components will be affected. Check wiring between A/C pressure sensor terminal No. 3 and ECM terminal B29, tank pressure sensor terminal No. 1 and ECM terminal B15, accelerometer terminal No. 1 and ECM terminal B1, and atmospheric pressure sensor terminal No. 1 and ECM terminal B29.
  9. Turn ignition off. Ensure fuel tank pressure sensor is connected. Disconnect atmospheric pressure sensor, A/C pressure sensor, and accelerometer. Turn ignition on. Measure voltage between atmospheric pressure sensor terminal No. 1 and ground. If voltage is approximately 5 volts, go to next step. If voltage is not approximately 5 volts, replace fuel tank pressure sensor.
  10. Turn ignition off. Ensure A/C pressure sensor is connected. Disconnect atmospheric pressure sensor and accelerometer. Turn ignition on. Measure voltage between atmospheric pressure sensor terminal No. 1 and ground. If voltage is approximately 5 volts, replace accelerometer. If voltage is not approximately 5 volts, replace A/C pressure sensor.
  11. If fault is permanent, and signal is too low, turn ignition off. Disconnect atmospheric pressure sensor. Turn ignition on. Measure voltage between atmospheric pressure sensor connector terminal No. 1 and ground. If voltage is approximately 5 volts, go to next step. If voltage is not approximately 5 volts, go to step 13 .
  12. Turn ignition off. Wait approximately 150 seconds (2.5 minutes). Disconnect atmospheric pressure sensor. Connect DVOM between atmospheric pressure sensor connector terminal No. 3 and ground. If DVOM reading is more than 0.2 megohms, go to next step. If DVOM reading is less than 0.2 megohms, check for a short to ground in wiring between atmospheric pressure sensor terminal No. 3 and ECM connector terminal B22.
  13. Turn ignition off. Ensure atmospheric pressure sensor is connected. Start and idle engine. Using scan tool, go into scrolling value list. If atmospheric pressure sensor signal value is approximately 4.5 volts at sea level and normal atmospheric pressure, cause of DTC is poor or loose connection at atmospheric pressure sensor connector. Check connector for poor terminal contact. Repair as necessary. If atmospheric pressure sensor signal value is not approximately 4.5 volts at sea level and normal atmospheric pressure, replace atmospheric pressure sensor.
  14. Turn ignition off. Ensure atmospheric pressure sensor is disconnected. Wait approximately 2 minutes. Connect DVOM between atmospheric pressure sensor connector terminal No. 1 and ground. If DVOM reads approximately 200-1500 ohms, system is okay. If DVOM reads less than 200-1500 ohms, go to next step. If DVOM reads more than 200-1500 ohms, go to step 18 .
  15. Turn ignition off. Ensure atmospheric pressure sensor is disconnected. Disconnect accelerometer. Connect DVOM between atmospheric pressure sensor connector terminal No. 1 and ground. If DVOM reads 200-1500 ohms, replace accelerometer. If DVOM does not read 200-1500 ohms, go to next step.
  16. Turn ignition off. Ensure atmospheric pressure sensor and accelerometer are disconnected. Disconnect fuel tank pressure sensor. Connect DVOM between atmospheric pressure sensor connector terminal No. 1 and ground. If DVOM reads approximately 200-1500 ohms, replace fuel tank pressure sensor. If DVOM does not read approximately 0.2-1.5 k/ohms, go to next step.
  17. Turn ignition off. Ensure atmospheric pressure sensor, fuel tank pressure sensor, accelerometer, and A/C pressure sensor are disconnected. Turn ignition on. Connect DVOM between atmospheric pressure sensor terminal No. 1 and ground. If DVOM reads approximately 200-1500 ohms, replace A/C pressure sensor. If DVOM does not read approximately 200-1500 ohms, go to next step.
  18. Atmospheric pressure sensor power lead is connected inside ECM to A/C pressure sensor, fuel tank pressure sensor, and accelerometer power leads. If anything happens to any of these power leads all 4 components will be affected. Check wiring between A/C pressure sensor terminal No. 3 and ECM terminal B29, tank pressure sensor terminal No. 1 and ECM terminal B15, and accelerometer terminal No. 1 and ECM terminal B29. Repair as necessary.
  19. Turn ignition off. Ensure atmospheric pressure sensor is disconnected. Check ECM connector for poor terminal contact. Repair as necessary. Reconnect ECM connector. Connect DVOM between atmospheric pressure sensor connector terminal No. 1 and ground. If DVOM reads approximately 200-1500 ohms, DTC was caused by poor ECM terminal contact. If DVOM does not read 200-1500 ohms, check for an open circuit in wiring between atmospheric pressure sensor terminal No. 31 and ECM connector terminal B29.
  20. If fault is permanent, and signal is sporadic, Turn ignition off. Check atmospheric pressure sensor connector for good terminal contact. Repair as necessary. Check ECM connector for good terminal contact. Repair as necessary. Reconnect atmospheric pressure sensor and ECM connectors. Start and idle engine. Wait 5 minutes. Check DTCs. If DTC 422 is stored and does not have intermittent fault status, go to next step. If DTC is stored and does have intermittent fault status, cause of DTC was poor connection at atmospheric pressure sensor and/or ECM.
  21. Check for an intermittent open or short circuit to ground or voltage in wiring between atmospheric pressure sensor terminal No. 1 and ECM connector terminal B29, between atmospheric pressure sensor terminal No. 3 and ECM connector terminal B22, and between atmospheric pressure sensor terminal No. 2 and ECM connector terminal B28. Repair as necessary. If wiring is okay, go to next step.
  22. Atmospheric pressure sensor power lead is connected inside ECM to A/C pressure sensor, fuel tank pressure sensor, and accelerometer power leads. If a fault occurs in any of these wires all 4 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 connector terminal B29, tank pressure sensor terminal No. 1 and ECM connector terminal B15, and accelerometer terminal No. 1 and ECM connector terminal B1. Repair as necessary. Check DTCs. If DTC 422 is stored with intermittent fault status, system is okay. If DTC 422 is stored with permanent status, go to next step.
  23. Turn ignition off. Ensure atmospheric pressure sensor is connected. Disconnect A/C pressure sensor. Start and idle engine. Wait 5 minutes. Check DTCs. If DTC 422 is stored with intermittent fault status, replace A/C pressure sensor. If DTC 422 is stored with permanent fault status, go to next step.
  24. Turn ignition off. Ensure atmospheric pressure sensor and A/C pressure sensor are connected. Disconnect accelerometer connector. Start and idle engine. Wait 5 minutes. Check DTCs. If DTC 422 is stored with intermittent fault status, replace accelerometer. If DTC 422 is stored with permanent fault status, go to next step.
  25. Turn ignition off. Ensure atmospheric pressure sensor and accelerometer are connected. Disconnect fuel tank pressure sensor. Start and idle engine. Wait 5 minutes. Check DTCs. If DTC 422 is stored with intermittent fault status, replace tank pressure sensor. If DTC 422 is stored with permanent fault status, replace atmospheric pressure sensor.
  26. If fault is intermittent, signal too high, check atmospheric pressure sensor and ECM connectors for poor terminal contact. Repair as necessary. Also check for an intermittent open circuit or short circuit to voltage in wiring between atmospheric pressure sensor terminal No. 3 and ECM connector terminal B22, atmospheric pressure sensor terminal No. 2 and ECM connector terminal B28, atmospheric pressure sensor terminal No. 1 and ECM connector terminal B29, A/C pressure sensor terminal No. 3 and ECM connector terminal B29, accelerometer terminal No. 1 and ECM connector terminal B1, and wiring between fuel tank pressure sensor terminal No. 1 and ECM connector terminal B15. Repair as necessary.
  27. If fault is intermittent, signal too low, check atmospheric pressure sensor and ECM connectors for poor terminal contact. Repair as necessary. Also check for an intermittent open or short circuit to ground in wiring between atmospheric pressure sensor terminal No. 3 and ECM connector terminal B22, atmospheric pressure sensor terminal No. 3 and ECM connector terminal B29, A/C pressure sensor terminal No. 3 and ECM connector terminal B29, accelerometer terminal No. 1 and ECM connector terminal B1, and fuel tank pressure sensor terminal No. 1 and ECM connector terminal B15.
  28. If fault is intermittent, signal sporadic, check atmospheric pressure sensor and ECM connectors for poor terminal contact. Repair as necessary. Also check for an intermittent open or short circuit to ground or voltage in wiring between atmospheric pressure sensor terminal No. 1 and ECM connector terminal B29, atmospheric pressure sensor terminal No. 3 and ECM connector terminal B22, and atmospheric pressure sensor terminal No. 2 and ECM connector terminal B28. Also note that atmospheric pressure sensor power lead is connected inside ECM to A/C pressure sensor, fuel tank pressure sensor, and accelerometer power leads. If a fault occurs in any of these wires all 4 components will be affected. Go to next step.
  29. Check for an intermittent short circuit to voltage or ground in wiring between A/C pressure sensor terminal No. 3 and ECM connector terminal B29, tank pressure sensor terminal No. 1 and ECM connector terminal B15, and accelerometer terminal No. 1 and ECM connector terminal B1. Repair as necessary.
  1. None
  1. If fault is permanent and signal is too high, go to next step. If fault is permanent, signal too low, go to step 8 . If fault is permanent, signal sporadic, go to step 9 . If fault is intermittent, signal too high or low, go to step 11 . If fault is intermittent, signal sporadic, go to step 12 .
  2. If fault is permanent and signal is too high, turn ignition off. Wait approximately 2 minutes. Disconnect outside temperature sensor Blue connector. Connect DVOM between outside temperature sensor connector terminal No. 2 and ground. If DVOM reads approximately zero ohms, go to next step. If DVOM does not read approximately zero ohms, go to step 4 .
  3. Turn ignition on. Disconnect temperature sensor connector. Measure voltage between ECM side of temperature sensor connector terminals No. 1 and 2. If voltage is approximately 5 volts, go to step 5 . If voltage is less than 5 volts, go to step 7 . If voltage is more than 5 volts, check for a short circuit to voltage in wiring between outside temperature sensor terminal No. 1 and ECM terminal A35. Repair as necessary, then go to step 6 .
  4. Turn ignition off. Disconnect temperature sensor connector. Check ECM connector terminals for poor terminal contact. Repair as necessary. Connect DVOM between ECM side of temperature sensor connector terminal No. 2 and ground. If DVOM reads approximately zero ohms, DTC was caused by poor terminal contact at ECM connector. If DVOM does not read approximately zero ohms, check for an open circuit in wiring between temperature sensor connector terminal No. 2 and ECM connector terminal A18.
  5. Connect DVOM between temperature sensor terminals No. 1 and 2. See «TEMPERATURE SENSOR RESISTANCE SPECIFICATIONS»(ref-15336-S22174311742000122900000) table. If resistances are within specification, DTC was caused by poor connection at outside temperature sensor connector. Repair as necessary. If resistances are not within specification, replace outside temperature sensor. TEMPERATURE SENSOR RESISTANCE SPECIFICATIONS Temperature °F (°C) Ohms 14 (-10) 2190-2270 32 (0) 1390-1420 50 (10) 890-930 68 (20) 590-630 86 (30) 400-430 104 (40) 270-300
  6. Turn ignition off. Disconnect temperature sensor connector. Connect DVOM between temperature sensor terminals No. 1 and 2. See «TEMPERATURE SENSOR RESISTANCE SPECIFICATIONS»(ref-15336-S22174311742000122900000) table. If resistances are to specification, temperature sensor is okay. If resistances are not to specification, replace temperature sensor.
  7. Turn ignition off. Disconnect temperature sensor and ECM connectors. Check ECM connector terminals for poor terminal contact and repair as necessary. Reconnect ECM connector. Turn ignition on. Measure voltage between temperature sensor connector terminals No. 1 and 2. If voltage is approximately 5 volts, DTC was caused by poor contact at ECM connector. If voltage is not approximately 5 volts, check for short circuit to voltage in wiring between temperature sensor connector terminal No. 1 and ECM terminal A35.
  8. If fault is permanent, and signal is too low, turn ignition on. Disconnect temperature sensor. Measure voltage between temperature sensor connector terminal No. 1 and ground. If approximately 5 volts are present, replace outside temperature sensor. If approximately 5 volts are not present, check wiring for a short to ground between temperature sensor terminal No. 1 and ECM terminal A35.
  9. If fault is permanent, and signal is sporadic, turn ignition off. Check temperature sensor Blue connector and ECM connector for poor terminal contact. Repair as necessary. Reconnect temperature sensor and ECM connectors. Start and idle engine. Wait 5 minutes. Use scan tool and access DTCs. If DTC 251 is stored and has permanent fault status, go to next step. If DTC 251 is stored and has intermittent fault status, repair connector terminal contact as necessary.
  10. Check outside temperature sensor and/or ECM connector terminals for poor terminal contact. Also check wiring for an intermittent open circuit, short circuit to ground, or short circuit to voltage between outside temperature sensor terminal No. 1 and ECM connector terminal A35, and outside temperature sensor terminal No. 2 and ECM connector terminal A18. Repair as necessary. If wiring is okay, replace outside temperature sensor.
  11. If fault is intermittent, signal too high, check outside temperature sensor and ECM connectors for poor terminal contact. Also check wiring for an intermittent open circuit or short circuit to voltage between outside temperature sensor terminal No. 1 and ECM terminal A35, and between temperature sensor terminal No. 2 and ECM terminal A18. If fault is intermittent, signal too low, check for an intermittent short circuit to ground in wiring between outside temperature sensor terminal No. 1 and ECM terminal A35.
  12. If fault is intermittent, signal sporadic, check outside temperature sensor and/or ECM connectors for poor terminal contact. Also check for intermittent short circuit to ground or voltage in wiring between outside temperature sensor harness connector terminal No. 1 and ECM terminal A35, and between outside temperature sensor harness connector terminal No. 2 and ECM terminal A18.

Diagnosis (Signal Too High)

WARNINGBefore beginning testing, disconnect engine cooling fan relay harness connector "A", to ensure cooling fan will not run. DTC P1619/EFI 514 may be stored. After fault-tracing, harness connector must be reconnected.

Note. ECM terminal A18 is a common ground for ECT sensor, Camshaft Position (CMP) sensor, and Throttle Position (TP) sensor.

  1. Connect scan tool. See «RETRIEVING & ERASING DTCs»(ref-15336-S41120021042000122900000) under SELF-DIAGNOSTIC SYSTEM. If no DTC's are stored, go to next step. If DTC P0120/EFI 411, DTC P0122/EFI 411, DTC P0123/EFI 411 or DTC P0340/EFI 314 are stored, check for contact resistance and oxidation at ECM terminal A18. Repair as necessary. After repairs, repeat step.
  2. On scan tool, if signal is PERMANENT, go to step 3. If signal is INTERMITTENT, check for loose connections at ECT sensor and ECM harness connectors. Repair as necessary. Check for an intermittent open and/or short to voltage in circuit between ECT sensor harness connector terminal No. 1 and ECM terminal A31. Repair as necessary. Check for intermittent open in circuit between ECT sensor harness connector terminal No. 2 and ECM terminal A18. Repair as necessary. After repairs, go to step 9.
  3. Turn ignition off. Wait approximately 3 minutes. Disconnect ECT sensor harness connector. Using DVOM, measure resistance between ground and ECT sensor harness connector terminal No. 2. Resistance should be approximately zero ohms. If resistance is within specification, go to next step. If resistance is not within specification, go to step 6.
  4. Turn ignition on. Using DVOM, measure voltage between ECT sensor harness connector terminals No. 1 and No. 2. Voltage should be approximately 5 volts. If voltage is more than specified, go to next step. If voltage is within specification, go to step 7. If voltage is less than specified, go to step 8.
  5. Check for short to voltage in circuit between ECT sensor harness connector terminal No. 1 and ECM terminal A31. Turn ignition off. Using DVOM, measure resistance between ECT sensor harness connector terminals No. 1 and No. 2. Resistance should be approximately 2,200 ohms at 77°F (25°C). (Scheme 23) If resistance is within specification, ECT sensor is okay. Go to step 9. If resistance is not within specification, replace ECT sensor. After repairs, go to step 9.
  6. Turn ignition off. Check for contact resistance and oxidation at ECM harness connector. Repair as necessary. Ensure ECM is securely connected. Using DVOM, check resistance between ground and ECT sensor harness connector terminal No. 2. Resistance should be approximately zero ohms. If resistance is within specification, DTC was caused by loose connections in ECM harness connector. Go to step 9. If resistance is not within specification, check for an open in circuit between ECT sensor harness connector terminal No. 2 and ECM terminal A18. Repair as necessary. After repairs, go to step 9.
  7. Turn ignition off. Using DVOM, check resistance between ECT sensor harness connector terminals No. 1 and No. 2. Resistance should be approximately 2,200 ohms at 77° F (25° C). (Scheme 23) If resistance is within specification, check for contact resistance and oxidation at ECT sensor harness connector. Repair as necessary. After repairs, go to step 9. If resistance is not within specification, replace ECT sensor. After repairs, go to step 9.
  8. Turn ignition off. Check for contact resistance and oxidation at ECM harness connector. Ensure ECM is securely connected. Turn ignition on. Using DVOM, measure voltage between ECT sensor harness connectors No. 1 and No. 2. Voltage should be approximately 5 volts. If voltage is within specification, DTC was caused by loose connections in ECM harness connector. Go to next step. If voltage is not within specification, check for an open in circuit between ECT sensor harness connector terminal No. 1 and ECM terminal A31. Repair as necessary. After repairs, go to next step.
  9. Turn ignition off. Reconnect all connectors and components. Connect DVOM with Volvo temperature box (999 5281) and Volvo temperature sensor (999 5282). Carefully remove expansion tank cap. Clamp hose between radiator and thermostat. Disconnect hose from thermostat housing. Insert sensor in thermostat housing and reinstall hose. Remove hose clamp. Start engine and warm until thermostat is open. Using scan tool in DIAGNOSTIC MODE, read ECT sensor. If ECT sensor is within specification, fault was corrected. If reading is not within specification, repeat test starting with step 1.

Scheme 23

Scheme 23
Scheme 23

Diagnosis (Signal Too Low)

WARNINGBefore beginning testing, disconnect engine cooling fan relay harness connector "A", to ensure cooling fan will not run. DTC P1619/EFI 514 may be stored. After fault-tracing, harness connector must be reconnected.

Note. ECM terminal A18 is a common ground for ECT sensor, Camshaft Position (CMP) sensor, and Throttle Position (TP) sensor.

  1. Connect scan tool. See «RETRIEVING & ERASING DTCs»(ref-15336-S41120021042000122900000) under SELF-DIAGNOSTIC SYSTEM. If no DTC's are stored, go to next step. If DTC P0120/EFI 411, DTC P0122/EFI 411, DTC P0123/EFI 411 or DTC P0340/EFI 314 are stored, check for contact resistance and oxidation at ECM terminal A18. Repair as necessary. After repairs, repeat step.
  2. If signal is PERMANENT go to next step. If signal is INTERMITTENT, check for intermittent short to ground in circuit between ECT sensor harness connector terminal No. 1 and ECM terminal A31. Repair as necessary. After repairs, go to step 4 .
  3. Disconnect ECT sensor harness connector. Turn ignition on. Using scan tool in DIAGNOSTIC MODE, scroll through values list. Read voltage for ECT sensor. Voltage should be approximately 5 volts. If voltage is within specification, replace ECT sensor. After repairs, go to next step. If voltage is not within specification, check for short to ground in circuit between ECT sensor harness connector terminal No. 1 and ECM terminal A31. Repair as necessary. After repairs, go to next step.
  4. Turn ignition off. Reconnect all connectors and components. Connect DVOM with Volvo temperature box (999 5281) and Volvo temperature sensor (999 5282). Carefully remove expansion tank cap. Clamp hose between radiator and thermostat. Disconnect hose from thermostat housing. Insert sensor in thermostat housing and reinstall hose. Remove hose clamp. Start engine and warm until thermostat is open. Using scan tool in DIAGNOSTIC MODE, read ECT sensor. If ECT sensor is within specification, fault was corrected. If reading is not within specification, repeat test starting with step 1 .

Diagnosis (Signal Faulty)

WARNINGBefore beginning testing, disconnect engine cooling fan relay harness connector "A", to ensure cooling fan will not run. DTC P1619/EFI 514 may be stored. After fault-tracing, harness connector must be reconnected.

Note. ECM terminal A18 is a common ground for ECT sensor, Camshaft Position (CMP) sensor, and Throttle Position (TP) sensor.

  1. Connect scan tool. See «RETRIEVING & ERASING DTCs»(ref-15336-S41120021042000122900000) under SELF-DIAGNOSTIC SYSTEM. If no DTC's are stored, go to next step. If DTC P0120/EFI 41, DTC P0122/EFI 41, DTC P0123/EFI 411 or DTC P0340/EFI 314 are stored, check for contact resistance and oxidation at ECM terminal A18. Repair as necessary. After repairs, repeat step.
  2. If signal is PERMANENT, go to next step. If signal is INTERMITTENT, check for loose connections, contact resistance and oxidation at ECT sensor and ECM harness connectors. Repair as necessary. Check for intermittent short to voltage and shorted condition in circuit between ECT sensor harness connector terminal No. 1 and ECM terminal A31. Repair as necessary. Check for intermittent open in circuit between ECT sensor harness connector terminal No. 2 and ECM terminal A18. Repair as necessary. After repairs, go to step 8 .
  3. Turn ignition off. Connect DVOM with Volvo temperature box (999 5281) and Volvo temperature sensor (999 5282). Carefully remove expansion tank cap. Clamp hose between radiator and thermostat. Loosen hose clamp, and disconnect hose from thermostat housing. Insert sensor in thermostat housing and reinstall hose. Remove hose clamp. Start engine and warm until thermostat is open. Using scan tool in DIAGNOSTIC MODE, read ECT sensor parameter. If ECT sensor is within specification, replace coolant thermostat. After repairs, go to step 8 . If reading is not within specification, go to next step.
  4. Disconnect ECT sensor harness connector. Turn ignition on. Using scan tool in DIAGNOSTIC MODE, scroll value list. Read ECT sensor voltage. Voltage should be approximately 5 volts. If voltage is within specification, go to step 6 . If voltage is not within specification, leave harness connector disconnected, and go to next step.
  5. Turn ignition off. Check for contact resistance and oxidation at ECM harness connector. Repair as necessary. Ensure ECM is securely connected. Turn ignition on. Using scan tool in DIAGNOSTIC MODE, scroll through value list. Read ECT sensor voltage parameter. Voltage should be approximately 5 volts. If voltage is within specification, DTC was caused by loose connection in ECM harness connector. Go to step 8 . If voltage is not within specification, check for short in circuit between ECT sensor harness connector terminal No. 1 and ECM terminal A31. Repair as necessary. After repairs go to step 8 .
  6. Turn ignition off. Wait approximately 3 minutes (5 minutes for vehicles equipped with immobilizer). Disconnect ECT sensor harness connector. Using DVOM, measure resistance between ground and ECT sensor harness connector terminal No. 2. Resistance should be approximately zero ohms. If resistance is not within specification, go to next step. If resistance is within specification, replace ECT sensor. After repairs, go to step 8 .
  7. Turn ignition off. Check for contact resistance and oxidation at ECM harness connector. Repair as necessary. Using DVOM, measure resistance between ground and ECT sensor harness connector terminal No. 2. Resistance should be approximately zero ohms. If resistance is not within specification, check for open in circuit between ECT sensor harness connector terminal No. 2 and ECM terminal A18. Repair as necessary. After repairs, go to next step. If resistance is within specification, DTC was caused by loose connections in ECM connector. Go to next step.
  8. Turn ignition off. Reconnect all connectors and components. Connect DVOM with Volvo temperature box (999 5281) and Volvo temperature sensor (999 5282). Carefully remove expansion tank cap. Clamp hose between radiator and thermostat. Loosen hose clamp and disconnect hose from thermostat housing. Insert sensor in thermostat housing and reinstall hose. Remove hose clamp. Start engine and warm until thermostat is open. Using scan tool in DIAGNOSTIC MODE, read ECT sensor parameter. If ECT sensor is within specification, fault was corrected. If reading is not within specification, repeat test starting with step 1 .
  1. Car feels sluggish
  2. High idling speed in neutral
  1. Check for other DTCs. If no other DTCs are stored, go to next step. If DTCs 123, 112 or 314 are stored, check Throttle Position (TP) sensor, ECT sensor and CMP sensor connector terminal A18 at ECM for contact resistance and oxidation.
  2. Check status message on Volvo Scan Tool (998-8686). If status message is PERMANENT FAULT, SIGNAL TOO HIGH, go to step 3 . If status message is PERMANENT FAULT, SIGNAL TOO LOW, go to step 10 . If status message is INTERMITTENT FAULT, SIGNAL TOO HIGH, go to step 14 . If status message is INTERMITTENT FAULT, SIGNAL TOO LOW, go to step 16 .
  3. Turn ignition off. Wait approximately 2 minutes. If engine cooling fan is running, wait for it to switch off. Disconnect TP sensor. Connect DVOM between TP sensor connector terminal No. 1 and ground. If DVOM reads approximately zero ohms, go to step 5 . If DVOM does not read approximately zero ohms, go to next step.
  4. Turn ignition off. Disconnect TP sensor. Disconnect ECM. Clean ECM connector of oxidation or other contact resistance. Reconnect ECM. Connect an DVOM between TP sensor connector terminal No. 1 and ground. If DVOM reads approximately zero ohms, DTC is caused by poor contact at ECM connector. If DVOM does not read approximately zero ohms, check wiring between TP sensor connector terminal No. 1 and ECM connector terminal A18 for an open circuit.
  5. Turn ignition on. Disconnect TP sensor. Measure voltage between TP sensor connector terminal No. 2 and ground. If voltage is approximately 5 volts, go to next step. If voltage is not approximately 5 volts, check wiring between TP sensor connector terminal No. 2 and ECM connector terminal A15 for a short circuit to voltage.
  6. Turn ignition on. Disconnect TP sensor. Measure voltage between TP sensor connector terminal No. 3 and ground. If voltage is approximately 5 volts, go to step 8 . If voltage is approximately zero volts, go to next step. If voltage is more than approximately 5 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 9 .
  7. Turn ignition off. Disconnect TP sensor. Disconnect ECM connector. Ensure ECM connector terminals are clean and tight. Reconnect ECM. Turn ignition on. Measure voltage between TP sensor connector terminal No. 3 and ground. If voltage is approximately 5 volts, DTC was caused by poor contact at ECM connector. If voltage is not approximately 5 volts, check wiring between TP sensor connector terminal No. 3 and ECM connector terminal A16 for an open circuit.
  8. Turn ignition off. Reconnect TP sensor. Start and run engine at idle. Using Volvo Scan Tool (998-8686), read off 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 TP sensor.
  9. Turn ignition off. Connect TP sensor. Start and idle engine. Using Volvo Scan Tool (998-8686), read off 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.
  10. If fault is permanent and signal is too low, turn ignition off. Wait approximately 2 minutes. Disconnect TP sensor. Connect DVOM between TP sensor connector terminal No. 2 and ground. If DVOM reads .4-.6 k/ohms, go to step 12 . If DVOM reads approximately zero ohms, check wiring between TP sensor connector terminal No. 2 and ECM connector terminal A15 for a short circuit to ground. If DVOM reads infinite resistance, go to next step.
  11. Turn ignition off. Disconnect TP sensor. Disconnect ECM connector. Ensure ECM connector terminals are clean and tight. Reconnect ECM connector. Turn ignition on. Measure voltage between TP sensor connector No. 2 and ground. If voltage is approximately 5 volts, DTC is caused by poor contact at ECM connector terminals. If voltage is not approximately 5 volts, check wiring between TP sensor connector terminal No. 2 and ECM connector terminal A15 for an open circuit.
  12. Turn ignition on. Disconnect TP sensor connector. Measure voltage between TP sensor connector terminal No. 3 and ground. If voltage is approximately 5 volts, go to next step. If voltage is not approximately 5 volts, check wiring between TP sensor connector terminal No. 3 and ECM connector terminal A16 for a short circuit to ground.
  13. Turn ignition off. Connect TP sensor. Start engine. Using Volvo Scan Tool (998-8686), read off 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.
  14. If fault is intermittent and signal is too high, turn ignition off. Disconnect TP sensor. Turn ignition on. Measure voltage between TP sensor connector terminal No. 2 and ground. If voltage is approximately 5 volts, go to next step. If voltage is not approximately 5 volts, check wiring between TP sensor connector terminal No. 2 and ECM connector terminal A15 for a short circuit to voltage.
  15. 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.
  16. 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.
  1. None
  1. If DTC P0135/EFI 521 & DTC P0141/EFI 522 are stored, perform diagnosis for these DTCs first. 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 Test Box (981-3190) to ECM. Turn ignition on. Measure voltage between test box pins No. 33 and 42. If voltage is approximately one volt, go to next step. If voltage is not approximately one volt, disconnect front HO2S connector. Turn ignition on. Recheck voltage between test box pins. If voltage is approximately one volt, install new front HO2S. If voltage is not approximately one volt, disconnect front and rear HO2S connectors and repeat test. If voltage is approximately one volt, install new rear HO2S. If voltage is not approximately one 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. Measure voltage between test box pins No. 32 and 42. If voltage is approximately 1.5 volts, go to next step. If voltage is not approximately 1.5 volts, turn ignition off. Disconnect front HO2S connector. Repeat test. If voltage is now approximately 1.5 volts, replace front HO2S. If voltage is not approximately 1.5 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. Measure voltage between test box pins No. 34 and 42. If voltage is now approximately 1.5 volts, replace rear HO2S. If voltage is not approximately 1.5 volts, check wiring between rear HO2S terminal No. 4 and ECM connector terminal A34 for a short to voltage.
  5. Connect Test Box (981-3190) to ECM. Turn ignition on. Measure voltage between test box pins No. 33 and 42. If voltage is approximately one volt, go to next step. If voltage is not approximately one volt, disconnect front HO2S connector. Turn ignition on. Recheck voltage between test box pins. If voltage is approximately one volt, install new front HO2S. If voltage is not approximately one volt, disconnect rear HO2S and repeat test. If voltage is approximately one volt, install new rear HO2S. If voltage is not approximately one 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. Measure voltage between test box pins No. 32 and 42. If voltage is approximately 1.5 volts, go to next step. If voltage is not approximately 1.5 volts, turn ignition off. Disconnect front HO2S connector. Repeat test. If voltage is now approximately 1.5 volts, replace front HO2S. If voltage is not approximately 1.5 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. Measure voltage between test box pins No. 34 and 42. If voltage is now approximately 1.5 volts, replace rear HO2S. If voltage is not approximately 1.5 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 DVOM between HO2S connector terminals No. 3 and 4. If at least 50 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 ohms are not present, replace front HO2S.
  9. Turn ignition off. Wait 2 minutes. Disconnect front HO2S connector. Connect DVOM between HO2S connector terminals No. 4 and ground. If at least 50 ohms are present, go to next step. If at least 50 ohms are not present, check HO2S and ECM connectors for good terminal contact. Repair as necessary. Repeat test. If at least 50 ohms are present, system is okay, If at least 50 ohms are not present, check wiring between rear HO2S connector terminal No. 4 and ECM connector terminal A34 for an open circuit.
  10. Turn ignition off. Connect DVOM between front HO2S connector terminal No. 3 and ground. If DVOM reads approximately 200 ohms, go to next step. If DVOM does not read approximately 200 ohms, check HO2S and ECM connectors for good terminal contact. Repair as necessary. Repeat test. If DVOM reads approximately 200 ohms, system is okay, If DVOM does not read approximately 200 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 0.45 volt then maintains between 0.1-0.9 volt within approximately 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. Also check wiring between Idle Air Control (IAC) valve terminal No. 3 and ECM connector terminal A11 for an intermittent short to coil signal wire. 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.
  1. May result in poor performance
  1. Check for other DTCs. If DTC 436 is stored, perform testing for that DTC first. If DTC 436 is not stored, go to next step.
  2. Perform a compression check on all cylinders. Repair as necessary. If compression is okay, go to next step.
  3. 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.
  1. May result in poor performance
  1. Check for other DTCs. If DTC 425 is stored, perform testing for that DTC first. If DTC 425 is not stored, go to next step.
  2. Perform a compression check on all cylinders. See ADJUSTMENTS article. Repair as necessary. If compression is okay, go to next step.
  3. 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.
  4. Turn ignition on. Remove throttle pulley cover. Connect fuel pressure gauge to system. 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.
  5. 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 approximately .8 volt. If voltage at rear HO2S drops to approximately zero volts, retest using new front HO2S. If voltage at rear HO2S does not drop to approximately zero volts, retest using new rear HO2S.
  1. None
  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 8 . If INTERMITTENT FAULT, SIGNAL TOO LOW is displayed, go to step 9 .
  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. Measure voltage between HO2S connector terminal No. 2 and ground. If voltage is approximately zero volts, retest using new HO2S. If voltage is not approximately 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, turn ignition off. Disconnect front HO2S Black connector and/or rear HO2S Gray connector. Turn ignition on. Measure voltage between HO2S connector terminal No. 1 and ground. If battery voltage is present, go to next step. If battery voltage is not present, check wiring between HO2S connector terminal No. 1 and main relay connector terminal No. 3 for an open circuit.
  4. Turn ignition on. Disconnect HO2S connector. Measure voltage between HO2S connector terminal No. 2 and ground. If voltage is approximately zero volts, go to next step. If voltage is not approximately 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.
  5. Turn ignition off. Wait approximately 2 minutes. Disconnect HO2S connector. Disconnect ECM. Connect DVOM between HO2S connector terminal No. 2 and ground. If DVOM reads infinite resistance, go to next step. If DVOM 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.
  6. Turn ignition off. Disconnect HO2S and ECM connectors. Connect Test Box (981-3190) to ECM connector. Check all grounds. See SYSTEM/COMPONENT TESTS article. Connect an DVOM between HO2S connector terminal No. 2 and test box pin No. 14 (DTC 521) or pin No. 29 (DTC 522). If DVOM reads approximately zero ohms, go to next step. If DVOM does not read approximately 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.
  7. Turn ignition off. Reconnect HO2S connector. Disconnect ECM connector. Connect DVOM between test box pins No. 27 and No. 14 (DTC 521) or No. 29 (DTC 522). If DVOM reads 1.5-13 ohms, DTC is caused by poor contact in ECM and/or HO2S connector. If DVOM does not read 1.5-13 ohms, retest using new HO2S.
  8. 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.
  9. 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.
  1. None
  1. If DTCs 522 or 212 are stored, perform diagnosis for these DTCs first. 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 Test Box (981-3190) to ECM. Turn ignition on. Measure voltage between test box pins No. 33 and 42. If voltage is approximately one volt, go to next step. If voltage is not approximately one volt, disconnect front HO2S connector. Turn ignition on. Recheck voltage between test box pins. If voltage is approximately one volt, install new front HO2S. If voltage is not approximately one volt, disconnect rear HO2S and repeat test. If voltage is approximately one volt, install new rear HO2S. If voltage is not approximately one 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. Repair as necessary.
  3. Turn ignition on. Measure voltage between test box pins No. 32 and 42. If voltage is approximately 1.5 volts, go to next step. If voltage is not approximately 1.5 volts, turn ignition off. Disconnect front HO2S connector. Repeat test. If voltage is now approximately 1.5 volts, replace front HO2S. If voltage is not approximately 1.5 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. Measure voltage between test box pins No. 34 and 42. If voltage is now approximately 1.5 volts, replace rear HO2S. If voltage is not approximately 1.5 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 DVOM between HO2S connector terminals No. 3 and 4. If at least 50 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 ohms are not present, replace rear HO2S.
  6. Turn ignition off. Wait 2 minutes. Disconnect rear HO2S connector. Connect DVOM between HO2S connector terminal No. 4 and ground. If at least 50 ohms are present, go to next step. If at least 50 ohms are not present, check HO2S and ECM connectors for poor terminal contact. Repair as necessary. Repeat test. If at least 50 ohms are present, system is okay, If at least 50 ohms are not present, check wiring between rear HO2S connector terminal No. 4 and ECM connector terminal A34 for an open circuit.
  7. Turn ignition off. Connect DVOM between rear HO2S connector terminal No. 3 and ground. If DVOM reads approximately 200 ohms, go to next step. If DVOM does not read approximately 200 ohms, check HO2S and ECM connectors for good terminal contact. Repair as necessary. Repeat test. If DVOM reads approximately 200 ohms, system is okay, If DVOM does not read approximately 200 ohms, check wiring between rear HO2S connector terminal No. 3 and ECM connector terminal A33 for an open circuit.
  8. Start and idle engine. Using scan tool, go into scrolling values list. If rear HO2S signal rises above middle value of .47 volt, then maintains 0.1-0.9 volt within approximately 10 minutes, 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. Also check wiring between Idle Air Control (IAC) valve terminal No. 3 and ECM connector terminal A11 for an intermittent short to coil signal wire. Repair as necessary.
  10. 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.
  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 loose connections. Repair as necessary.
  1. None
  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.
  1. Can result in high fuel consumption
  2. May result in poor performance

Diagnosis (Upper Limit)

  1. Check for other DTCs. If DTC P0440/EFI 315 is stored, perform testing on that DTC first. If DTC 315 is not stored, go to next step.
  2. Turn ignition on, with engine off. Ignition off. Connect mass air flow (MAF) sensor. Turn ignition on. Connect a voltmeter between Mass Air Flow (MAF) sensor connector terminals 2 and 4. The voltmeter should display 0.1-0.2 volt. If voltage is 0.1-0.2 volt, go to step 3 . If voltage is not 0.1-0.2 volt, retest using new MAF sensor.
  3. Check air leakage in the intake system. See «AIR INDUCTION SYSTEMS»(ref-15338-S04926055312000122900000) in SYSTEM/COMPONENT TESTS article. If there are no intake air leaks, go to step 4 . If there any intake air leaks, repair as necessary. After repairs, erase any stored DTCs.
  4. Check for air leakage in the exhaust system. See «EXHAUST SYSTEM»(ref-15338-S35406227492004092400000) in SYSTEM/COMPONENT TESTS article. If there are no exhaust air leaks, go to step 5 . If there are any exhaust air leaks, repair as necessary. After repairs, erase any stored DTCs.
  5. Check fuel pressure and residual fuel pressure. See «FUEL SYSTEM»(ref-15334-S40651218142000122900000) in BASIC TESTING article. If fuel pressure is OK, go to step 6 . If fuel pressure is NOT OK, repair fuel system as necessary. After repairs, erase any stored DTCs.
  6. Check fuel pulsation damper. Connect scan tool to DLC. Test drive vehicle at 1250 RPM on a flat road. Read off short term fuel trim and engine speed (RPM) values. Test value should read about 1.000. If reading is OK, go to step 7 . If test value does not vary at approximately 1.000, replace fuel pulsation damper mounted on fuel rail. Go to step 8 .
  7. Connect test (breakout) box to ECM and check ground connections. See «COMPUTERIZED ENGINE CONTROLS»(ref-15338-S24381785592000122900000) in SYSTEM/COMPONENT TESTS article. Reconnect ECM. Repair as necessary.
  8. Verification. Turn off ignition. Reconnect all connectors and install all components. Connect scan tool to DLC. Test drive car while monitoring long-term fuel trim value until it switches to completed. If DTC is stored, it should have status as intermittent fault.

Diagnosis (Lower Limit)

  1. Check for other DTCs. If DTC P0440/EFI 315 is stored, perform testing on that DTC first. If DTC 315 is not stored, go to next step.
  2. Turn ignition on, with engine off. Ignition off. Connect mass air flow (MAF) sensor. Turn ignition on. Connect a voltmeter between Mass Air Flow (MAF) sensor connector terminals 2 and 4. The voltmeter should display 0.1-0.2 volt. If voltage is 0.1-0.2 volt, go to step 3 . If voltage is not 0.1-0.2 volt, retest using new MAF sensor.
  3. Check for air leakage in the exhaust sytem. See «EXHAUST SYSTEM»(ref-15338-S35406227492004092400000) in SYSTEM/COMPONENT TESTS article. If there are no exhaust air leaks, go to step 4 . If there are any exhaust air leaks, repair as necessary. After repairs, erase any stored DTCs.
  4. Check fuel pressure and residual fuel pressure. See «FUEL SYSTEM»(ref-15334-S40651218142000122900000) in BASIC TESTING article. If fuel pressure is OK, go to step 5 . If fuel pressure is NOT OK, repair fuel system as necessary. After repairs, erase any stored DTCs.
  5. Checking canister purge valve. Remove hose to intake manifold from canister purge valve. Reinstall hose after fault-tracing. When installing use a new hose clamp. Connect vacuum pump to canister purge valve connector. Pump up a vacuum. The vacuum gauge should indicate a steady vacuum. If reading is OK, go to step 6 . If reading is incorrect, try a new canister purge valve. Erase any stored DTCs. Reset long-term fuel trim.
  6. Checking engine oil level Check engine oil level. The oil level should be between the MIN and MAX marks. Fill oil to correct level. Go to step 7 .
  7. Checking engine oil. Start the engine and idle it for a few minutes. Use scan tool to read off and note the value of the short-term fuel trim. Disconnect and plug crankcase ventilation. Read off the short-term fuel trim value again. This value should be more or less the same. If value is OK, go to step 8 . If reading is incorrect, this indicates that the engine oil is contaminated with fuel. Change engine oil and oil filter. Erase any stored DTCs. Reset long-term fuel trim.
  8. Connect test (breakout) box to ECM and check ground connections. See «COMPUTERIZED ENGINE CONTROLS»(ref-15338-S24381785592000122900000) in SYSTEM/COMPONENT TESTS article. Reconnect ECM. Repair as necessary. Go to step 9 .
  9. Verification. After carrying out the repair, check that the fault has been remedied. Turn ignition off. Reconnect connectors and reinstall components. Use the scan tool to read off the value of long-term fuel trim. Test drive the car. Watch the long-term fuel trim value until it switches to completed. If DTC EFI-231/232 is stored it should have intermittent status.
  1. Engine not firing on all cylinders
  2. The engine may not start
  1. If an injector circuit is shorted to ground or voltage, or if there is an open 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 DVOM between injector connector terminals No. 1 and 2. If DVOM does not indicate approximately 16 ohms, install new injector. If DVOM indicates approximately 16 ohms, check wiring between injector connector terminal No. 2 and ECM connector terminal A10 (DTC 115), A38 (DTC 125), A24 (DTC 135), A23 (DTC 145), or A9 (DTC 155) 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), A38 (DTC 125), A24 (DTC 135), A23 (DTC 145), or A9 (DTC 155) for a short to ground.
  5. To check for a PERMANENT FAULT, SIGNAL MISSING, turn ignition off. Disconnect injector. Turn ignition on. Measure voltage 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. Turn ignition on. Measure voltage between injector connector terminal No. 2 and ground. If voltage is approximately 6 volts, go to next step. If voltage is not approximately 6 volts, turn ignition off. Check ECM connector for good terminal contact. Reconnect ECM. Turn ignition on. Measure voltage between injector connector terminal No. 2 and ground. If voltage is approximately 6 volts, fault was caused by poor ECM connector contact. If voltage is not approximately 6 volts, check wiring between injector connector terminal No. 2 and ECM connector terminal A10 (DTC 115), A38 (DTC 125), A24 (DTC 135), A23 (DTC 145), or A9 (DTC 155) for an open circuit.
  7. Turn ignition off. Disconnect injector connector. Connect DVOM between injector connector terminals No. 1 and 2. If DVOM reads approximately 16 ohms, DTC is caused by poor contact in injector or ECM connector. If DVOM does not read approximately 16 ohms, replace injector.
  8. To check for an INTERMITTENT FAULT, SIGNAL TOO HIGH, check wiring between injector connector terminal No. 2 and ECM connector terminal A10 (DTC 115), A38 (DTC 125), A24 (DTC 135), A23 (DTC 145), or A9 (DTC 155) 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), A38 (DTC 125), A24 (DTC 135), A23 (DTC 145), or A9 (DTC 155) 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), A38 (DTC 125), A24 (DTC 135), A23 (DTC 145), or A9 (DTC 155) for an intermittent open circuit.
  1. Improved or impaired performance due to excessively high or excessively low boost pressure
  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 permanent and signal is missing, go to step 4 . If fault is intermittent and signal is too high or low, go to step 8 . If fault is intermittent and signal is missing, go to step 9 .
  2. If fault is permanent and signal is too high, turn ignition off. Disconnect turbocharger (TC) control valve. Connect DVOM between TC control valve connector terminals No. 1 and 2. If DVOM reads approximately 24 ohms at 68°F (20°C), check for a short circuit to voltage in wiring between TC control valve terminal No. 2 and ECM connector terminal B41. If DVOM does not read approximately 24 ohms at 68°F (20°C), replace TC control valve.
  3. If fault is permanent and signal is too low, check for a short circuit to ground in wiring between TC control valve terminal No. 2 and ECM connector terminal B41. Repair as necessary.
  4. If fault is permanent and signal is missing, turn ignition off. Disconnect TC control valve. Turn ignition on. Measure voltage between TC control valve connector terminal No. 1 and ground. If battery voltage is present, go to next step. If battery voltage is not present, check wiring between TC control valve terminal No. 1 and main relay terminal No. 3 for an open circuit. Repair as necessary.
  5. Measure voltage between TC control valve connector terminal No. 2 and ground. If approximately 6 volts are present, go to next step. If approximately 6 volts are not present, go to step 7 .
  6. Turn ignition off. Connect DVOM between TC control valve connector terminals No. 1 and 2. If DVOM reads approximately 24 ohms at 68°F (20°C), cause of DTC was loose connection in TC control valve and/or ECM. Check connectors for poor terminal contact and repair as necessary. If DVOM does not read approximately 24 ohms at 68°F (20°C), replace TC control valve.
  7. Turn ignition off. Disconnect ECM connector and check for poor terminal contact. Repair as necessary. Reconnect ECM connector. Turn ignition on. Measure voltage between TC control valve connector terminal No. 2 and ground. If approximately 6 volts are present, DTC was caused by poor contact at ECM connector. If approximately 6 volts are not present, check wiring between TC control valve terminal No. 2 and ECM terminal B41 for an open circuit. Repair as necessary.
  8. If fault is intermittent and signal is too high, check wiring between TC control valve terminal No. 2 and ECM terminal B41 for an intermittent short circuit to voltage. Repair as necessary. If fault is intermittent and signal is too low, check wiring between TC control valve terminal No. 2 and ECM terminal B41 for an intermittent short circuit to ground.
  9. If fault is intermittent and signal is missing, check TC control valve and/or ECM connector for poor terminal contact. Repair as necessary. If terminal contact is okay, check for an intermittent open circuit in wiring between TC control valve terminal No. 1 and main relay terminal No. 3, and wiring between TC control valve terminal No. 2 and ECM terminal B41. Repair as necessary.
  1. Fuel injection is interrupted when boost pressure reaches its maximum limit. Because of this the engine runs very unevenly.
  2. Poor performance due to initial boost pressure.
  1. Turn ignition on. Ensure Mass Airflow (MAF) sensor is connected. Using voltmeter, backprobe between MAF sensor connector terminals No. 2 and 4. If voltage is .1-.2 volts, go to step 3 . If voltage is not approximately .1-.2 volts, go to next step.
  2. Turn ignition off. Check MAF and ECM connectors for poor terminal contact. Repair as necessary. Reconnect connectors. Turn ignition on. Using voltmeter, backprobe between MAF sensor connector terminals No. 2 and 4. If voltage is .1-.2 volts, DTC was caused by poor terminal contact at MAF and/or ECM connector. If voltage is not .1-.2 volts, replace MAF sensor.
  3. Turn ignition off. Connect test box and check ECM ground connections for good terminal contact. See WIRING DIAGRAMS. Repair as necessary. Disconnect ECM. Turn ignition on. Measure voltage between ground and test box pin No. 42. If battery voltage is present, go to next step. If battery voltage is not present, check wiring for an open circuit.
  4. Turn ignition off. Check Turbocharger (TC) control valve and Engine Control Module (ECM) connectors for poor terminal contact. Repair as necessary. Reconnect TC and ECM connectors. Turn ignition on. Using scan tool, activate TC control valve. If TC control valve operates, go to next step. If TC control valve does not operate, replace TC control valve.
  5. Turn ignition off. Ensure hose between TC and TC control valve, and hose between TC control valve and pressure servo to Boost Pressure Control (BPC) valve is not blocked or pinched. Also ensure TC control valve is not blocked between Red and Yellow connectors. If hoses and TC control valve are okay, go to next step. If hoses and TC control valve are not okay, clean and replace as necessary.
  6. Turn ignition off. Disconnect pressure servo hose. Connect Manometer (999 5230) and Pressure Tester (998 5496) to pressure servo. Pump pressure up to approximately 16.7 psi. If pressure servo is not fully open at this pressure, replace pressure servo. If pressure servo is fully open at this pressure, check basic adjustment of push rod. Connect manometer and pressure tester to pressure servo. Pump up pressure to approximately 0.14 psi. Push Boost Pressure Control (BPC) valve spindle toward Turbocharger (TC) housing. Adjust push rod so it fits onto spindle lug exactly. Install lock pin to BPC valve spindle. Tighten push rod lock nut. Remove manometer and pressure tester.
  7. Verification. After carrying out the repair, check that the fault has been remedied as follows. Reconnect connectors and reinstall components. Erase DTCs using scan tool. Test drive the car. Depress the accelerator pedal to the floor a few times. Read off any DTCs. DTC EFI-414 should not be stored.
  1. Engine not firing on all cylinders
  2. Engine may not start

Diagnosis (Signal Too High, Permanent Fault)

  1. Turn off ignition. Unplug injector. Connect an ohmmeter between injector terminals No. 1 and No. 2 (on injector). Ohmmeter should read about 16 ohms at 68°F (20°C).
  2. If reading is NOT OK, go to step 4 .
  3. If reading is OK, check wire between injector terminal No. 2 and the following ECM pin terminals for a short to battery voltage. After checking wire, go to step 4 . DTC P0261/EFI 115 & DTC P0262/EFI 115: ECM terminal A10 DTC P0264/EFI 125 & DTC P0265/EFI 125: ECM terminal A38 DTC P0267/EFI 135 & DTC P0268/EFI 135: ECM terminal A24 DTC P0270/EFI 145 & DTC P0271/EFI 145: ECM terminal A23 DTC P0273/EFI 155 & DTC P0274/EFI 155: ECM terminal A9
  4. After carrying out repair, check that the fault has been remedied. Connect scan tool to DLC. Using scan tool, activate relevant injector. A clicking sound should be heard from the injector when it is working. If aftermarket scan tool is not capable of activating injector, test drive vehicle and check if symptoms are gone and DTC does not reset.

Diagnosis (Signal Too Low, Permanent Fault)

  1. Check wire between injector teminal No. 2 and the following ECM pin terminals for a short to ground. After checking wire, go to step 2 . DTC P0261/EFI 115 & DTC P0262/EFI 115: ECM terminal A10 DTC P0264/EFI 125 & DTC P0265/EFI 125: ECM terminal A38 DTC P0267/EFI 135 & DTC P0268/EFI 135: ECM terminal A24 DTC P0270/EFI 145 & DTC P0271/EFI 145: ECM terminal A23 DTC P0273/EFI 155 & DTC P0274/EFI 155: ECM terminal A9
  2. After carrying out repair, check that the fault has been remedied. Connect scan tool to DLC. Using scan tool, activate relevant injector. A clicking sound should be heard from the injector when it is working. If aftermarket scan tool is not capable of activating injector, test drive vehicle and check if symptoms are gone and DTC does not reset.

Diagnosis (Signal Missing, Permanent Fault)

  1. Turn off ignition. Unplug injector. Turn ignition on, with engine off. Connect a voltmeter between injector connector terminal No. 1 and ground. Voltmeter should read battery voltage.
  2. If reading is OK, go to next step. If reading is not OK, check wire between injector terminal No. 1 and main relay (2/32), terminal No. 3, for an open circuit. Repair as necessary. Go to step 6 .
  3. Turn on ignition, with engine off. Leave injector disconnected. Connect a voltmeter between injector terminal No. 2 and ground. Voltmeter should read about 6 volts. If reading is OK, go to next step. If reading is NOT OK, go to step 5 .
  4. Turn off ignition, leave injector disconnected. Connect an ohmmeter between injector connector terminal No. 1 and No. 2 (on injector). Resistance should be about 1 ohms at 68°F (20°C). If reading is incorrect, replace injector. Go to step 6 . If resistance is OK, DTC is caused by poor contact in injector or ECM connector. Check for loose or corroded contacts. Repair as necessary. Go to step 6 .
  5. Turn off ignition, leave injector disconnected. Unplug ECM connector A. Check ECM connector for contact resistance and oxidation. Repair, as necessary. Reconnect ECM. Turn on ignition, with engine off. Connect a voltmeter between injector terminal No. 2 and ground. Voltmeter should read about 6 volts. If reading is OK, go to DTC was caused by poor contact in ECM connector. Go to step 6 . If voltage was not correct, check wire injector terminal No. 2 and ECM for an open circuit. Repair as necessary. Go step 6 .
  6. After carrying out repair, check that the fault has been remedied. Connect scan tool to DLC. Using scan tool, activate relevant injector. A clicking sound should be heard from the injector when it is working. If aftermarket scan tool is not capable of activating injector, test drive vehicle and check if symptoms are gone and DTC does not reset.

Diagnosis (Signal Too High, Intermittent Fault)

Check wire between injector terminal No. 2 and the following ECM pin terminals for an intermittent short to battery voltage.

  1. DTC P0261/EFI 115 & DTC P0262/EFI 115: ECM terminal A10
  2. DTC P0264/EFI 125 & DTC P0265/EFI 125: ECM terminal A38
  3. DTC P0267/EFI 135 & DTC P0268/EFI 135: ECM terminal A24
  4. DTC P0270/EFI 145 & DTC P0271/EFI 145: ECM terminal A23
  5. DTC P0273/EFI 155 & DTC P0274/EFI 155: ECM terminal A9

Diagnosis (Signal Too Low, Intermittent Fault)

Check wire between injector terminal No. 2 and the following ECM pin terminals for an intermittent short to ground.

  1. DTC P0261/EFI 115 & DTC P0262/EFI 115: ECM terminal A10
  2. DTC P0264/EFI 125 & DTC P0265/EFI 125: ECM terminal A38
  3. DTC P0267/EFI 135 & DTC P0268/EFI 135: ECM terminal A24
  4. DTC P0270/EFI 145 & DTC P0271/EFI 145: ECM terminal A23
  5. DTC P0273/EFI 155 & DTC P0274/EFI 155: ECM terminal A9

Diagnosis (Signal Missing, Intermittent Fault)

  1. Check injector and ECM connectors for loose connections. Also check for contact resistance and oxidation. Repair as necessary.
  2. Check the wire between injector terminal No. 1 and main relay terminal No. 3 for an intermittent open circuit.

Check wire between injector terminal No. 2 and the following ECM pin terminals for an intermittent open circuit.

  1. DTC P0261/EFI 115 & DTC P0262/EFI 115: ECM terminal A10
  2. DTC P0264/EFI 125 & DTC P0265/EFI 125: ECM terminal A38
  3. DTC P0267/EFI 135 & DTC P0268/EFI 135: ECM terminal A24
  4. DTC P0270/EFI 145 & DTC P0271/EFI 145: ECM terminal A23
  5. DTC P0273/EFI 155 & DTC P0274/EFI 155: ECM terminal A9

Fault Conditions (DTC EFI-45x, EFI-543

If the ECM registers more than 0.5% misfires in 1.000 engine revolutions (2500 ignition sequences), the ECM checks whether this misfiring comes from one specific cylinder or from different cylinders. If only one cylinder exceeds the limit, DTC EFI-543 is stored first and then one of DTCs EFI-451, EFI-452, EFI-453, EFI-454 or EFI-455, depending on the cylinder. If more than one cylinder exceeds the limit DTC EFI-543 is stored with a DTC for the relevant cylinder.

Fault Conditions (DTC EFI-55x, EFI-545

If the ECM registers misfiring to such a degree that the three-way catalytic converter (TWC) could be damaged (this degree varies with engine speed and load), for 200 engine revolutions (500 ignition sequences), the ECM checks whether the misfiring is coming from a specific cylinder or from different cylinders.

If only one cylinder exceeds the limit, DTC EFI-x is stored first with one of DTCs EFI-451, EFI-452, EFI-453, EFI-454 or EFI-456 and EFI-543, first DTC EFI-545 and then one of DTCs EFI-551, EFI-552, EFI-553, EFI-554 or EFI-555 depending on the cylinder. If more than one cylinder exceeds the limit, DTC EFI-545 is stored with a DTC for the relevant cylinder.

  1. Engine does not start, or is difficult to start
  2. Engine runs unevenly at idling speed, or jerkily while driving
  3. Poor performance
  4. High emissions
  5. Glowing pieces of three-way catalytic converter (TWC) falling out of the exhaust pipe

Substitute Value (DTC EFI-45x, EFI-543)

  1. Fuel trim with rear heated oxygen sensor (HO2S) disabled
  2. Long-term fuel trim disabled
  3. Three-way catalytic converter (TWC) diagnostic disabled
  4. Heated oxygen sensor (HO2S) diagnostic disabled

Substitute Value (DTC EFI-55x, EFI-545)

  1. Fuel trim for both heated oxygen sensors (HO2S) disabled
  2. Heated oxygen sensor (HO2S) aging diagnostic disabled
  3. Long-term fuel trim disabled
  4. Three-way catalytic converter (TWC) diagnostic disabled
  5. EVAP diagnostic is disabled
  6. Short circuit in heated oxygen sensor (HO2S) signal cable and ground lead blocked

Possible Causes (Not Included In Diagnosis, But May Still Set A DTC

  1. Fuel stoppage
  2. Water in spark plug wells
  3. Contaminated fuel or incorrect fuel
  4. Repeated cold starting where the engine coolant temperature (ECT) is not allowed to reach operating temperature between starts
  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 off all other misfiring DTCs. If DTC indicates misfiring has occurred in several cylinders, go to step 6 . If misfiring occurred in one cylinder, go to next step.
  3. Check all spark plugs, cylinder compression, cooling system, ignition wiring, and distributor cap and rotor. See ADJUSTMENTS article. Repair as necessary. If all components are okay, use Volvo Scan Tool (998-8686), or equivalent aftermarket scan tool, and check flywheel. Start engine and run at idle. Read off flywheel values on scan tool for adoption values "B", "C", "D" and "E". 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, retest using new flywheel.
  4. 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.
  5. 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.
  6. If misfiring is occurring in several cylinders, remove spark plugs and perform a compression test. See ADJUSTMENTS article. Repair as necessary. If compression is okay, go to next step.
  7. Checking cooling system. Connect Pressure Tester (998 5496) to expansion tank. Pump up pressure to approximately 14.5 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.
  8. Remove all ignition wires. Check wires for cracks or arcing. Measure resistance in each ignition wire. Depending on length, resistance should be 1500-4500 ohms. Replace ignition wires as necessary. If wires are okay, go to next step.
  9. Remove distributor cap and rotor. Check distributor cap and rotor for cracks, arcing, or other signs of damage. Replace as necessary. If cap and rotor are okay, go to next step.
  10. Turn ignition off. Disconnect cable terminal from ignition coil connector terminal No. 15. Connect an DVOM between ignition coil terminals No. 1 and 15. If DVOM reads 0.5-1.5 ohms, go to next step. If DVOM does not read 0.5-1.5 ohms, retest using new ignition coil, then go to step 12 .
  11. Turn ignition off. Disconnect ignition coil high tension wire. Connect an DVOM between ignition coil terminal No. 15 and high tension connector on ignition coil. If DVOM reads 8000-9000 ohms, go to next step. If DVOM does not read 8000-9000 ohms, retest using new ignition coil. Go to next step.
  12. Install new spark plugs. Install distributor cap and connect all ignition wiring. Connect cable terminal to ignition coil. Start engine and run at idle. Measure voltage between ignition coil connector terminal No. 15 and ground. If battery voltage is present, go to next step. If battery voltage is not present, check voltage supply connectors at junction box.
  13. Turn ignition off. Wait approximately 2 minutes. Disconnect Ignition Discharge Module (IDM) 4-pin connector. Connect DVOM between IDM connector terminal No. 1 and ground. If DVOM reads approximately zero ohms, go to next step. If DVOM does not read approximately zero ohms, check power stage ground connector for poor terminal contact. Repair as necessary, then go to next step.
  14. Check wiring between IDM connector terminal No. 4 and ECM connector terminal B11, wiring between IDM connector terminal No. 1 and ground, and wiring between IDM connector terminal No. 3 and battery voltage for an intermittent open circuit, short circuit to ground, or short circuit to voltage. Ensure all connectors are clean and tight. Repair as necessary, then go to next step.
  15. Start engine and run at idle. Using Volvo Scan Tool (998-8686), read off flywheel adoption values "B", "C", "D" and "E". If readings are -39 to +387, go to next step. If readings are not -39 to +387, check RPM sensor tip and hole down by flywheel/connecting flange for damage, scratches, and metal shavings. Repair as necessary. If RPM sensor and hole are okay, retest using new flywheel.
  16. Check wiring between injector connector terminal No. 1 and main relay terminal No. 3, and wiring between ECM connector terminal A41 and main relay connector terminal No. 1 for an intermittent open circuit. Also check connectors at injectors, main relay, and ECM for loose connection. Repair as necessary. Go to next step.
  17. Check wiring between ECM connector terminal B27 and fuel pump relay connector terminal No. 4, wiring between fuel pump relay connector terminal No. 2 and ground, wiring between battery positive terminal and fuel pump connector terminal No. 1, wiring between fuel pump relay connector terminal No. 3 and fuel pump connector terminal No. 1, and wiring between fuel pump connector terminal No. 2 and ground. Also check all connectors for good terminal contact. Repair as necessary. Go to next step.
  18. Check intake and exhaust systems for air leakage. Check engine oil level. Check fuel and residual pressure. Repair as necessary. If all checks are okay, system is operating normally.
  1. Poor performance due to retarded ignition
  1. If fault is permanent, go to next step. If fault is intermittent, turn ignition off. Wait 2 minutes. Disconnect knock sensor(s). Connect DVOM between knock sensor connector terminal No. 1 and ground. If DVOM reads approximately one megohm, system is okay. If DVOM does not read approximately one megohm, check wiring between knock sensor harness connector terminal No. 1 and ECM connector terminal A2 (DTC 142) or terminal A30 (DTC 433) for a short to ground.
  2. Turn ignition off. Wait 2 minutes. Disconnect knock sensor. Connect an DVOM between knock sensor connector terminal No. 2 and ground. If DVOM reads approximately zero ohms, go to step 4 . If DVOM does not read approximately zero ohms, go to next step.
  3. Turn ignition off. Ensure knock sensor is disconnected. Ensure ECM connector is making good electrical contact and is connected securely to ECM. Connect an DVOM between knock sensor connector terminal No. 2 and ground. If DVOM reads approximately zero ohms, DTC was caused by poor contact in ECM connector. If DVOM does not read approximately zero ohms, check wiring between knock sensor connector terminal No. 2 and ECM connector terminal A17 for an open circuit.
  4. Turn ignition off. Ensure knock sensor is disconnected. Connect an DVOM between knock sensor connector terminal No. 1 and ground. If DVOM reads approximately 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 DVOM reads approximately one megohm, go to step 6 . If DVOM reads infinite resistance, go to next step.
  5. Turn ignition off. Ensure knock sensor is disconnected. Ensure ECM connector terminals are free of resistance and oxidation. Reconnect ECM. Connect an DVOM between knock sensor connector terminal No. 1 and ground. If DVOM reads approximately one megohm, DTC is caused by poor terminal contact at ECM connector. If DVOM does not read approximately one megohm, check wiring between knock sensor connector terminal No. 1 and ECM connector terminal A2 (DTC 143) or terminal A30 (DTC 433) for an open circuit.
  6. Reconnect knock sensor(s). Start and warm up engine. Increase engine speed to slightly more than 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 more than 3500 RPM, source of DTC is poor contact at knock sensor connector. If knock sensor value is not 2-6 at speeds more than 3500 RPM, retest system using a new knock sensor.
  1. Engine does not start
  2. Engine cuts out
  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 DVOM between RPM sensor connector terminals No. 1 and 2. If DVOM shows approximately 200-500 ohms, go to next step. If DVOM does not show 200-500 ohms, replace RPM sensor.
  2. Turn ignition off. Wait 2 minutes. Ensure RPM sensor is disconnected. Connect an DVOM between ground and RPM sensor connector terminal No. 2. If DVOM does not read approximately zero ohms, go to next step. If DVOM reads approximately zero ohms, go to step 5 .
  3. Turn ignition off. Disconnect RPM sensor connector. Ensure ECM connectors and grounds are clean and tight. Reconnect ECM. Connect an DVOM between ground and RPM sensor connector terminal No. 2. If DVOM reads approximately zero ohms, go to next step. If DVOM does not read approximately 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. Connect an DVOM between ground and RPM sensor connector terminal No. 1. If DVOM reads 15-25 k/ohms, go to step 6 . If DVOM shows higher resistance, go to next step. If DVOM shows approximately 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 DVOM between ground and RPM sensor connector terminal No. 1. If DVOM reads 15-25 k/ohms, source of DTC was poor contact at ECM connector. If DVOM 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. Measure voltage between RPM sensor connector terminals. If voltage is 1-2 volts, go to next step. If voltage is not 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. 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, test using new RPM sensor.
  1. Engine runs erratically
  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.
  1. Engine does not start
  1. Check for other DTCs. If no other DTCs are present, go to next step. If DTCs 123 or 411 are stored, check TP sensor, ECT sensor and CMP connection at ECM connector terminal A18 for signs of contact resistance and oxidation.
  2. Using Volvo Scan Tool (998-8686) check status message. If fault is permanent, go to next step. If fault is intermittent, go to step 10 .
  3. Turn ignition off. Wait approximately 2 minutes. Disconnect CMP. Connect an DVOM between CMP connector terminal No. 1 and ground. If DVOM reads approximately zero ohms, go to step 5 . If DVOM does not read approximately zero ohms, go to next step.
  4. Turn ignition off. Disconnect ECM connector. Disconnect CMP connector. Ensure ECM connector terminals are clean and free of oxidation. Reconnect ECM connector. Connect an DVOM between CMP terminal No. 1 and ground. If DVOM reads approximately zero ohms, source of DTC is poor contact in ECM connector. If DVOM does not read approximately zero ohms, check wiring between CMP connector terminal No. 1 and ECM connector terminal A18 for an open circuit.
  5. Turn ignition on. Disconnect CMP connector. Measure voltage between CMP connector terminal No. 3 and ground. If battery voltage is present, go to step 7 . If battery voltage is not present, go to next step.
  6. Turn ignition off. Disconnect CMP connector. Ensure ECM connector terminals are clean and free of oxidation. Reconnect ECM. Turn ignition on. Measure voltage between CMP connector terminal No. 3 and ground. If battery voltage is present, source of DTC is poor contact in ECM connector. If battery voltage is not present, check wiring between CMP sensor connector terminal No. 3 and ECM connector terminal A36 for an open circuit.
  7. Turn ignition on. Disconnect CMP connector. Measure voltage between CMP connector terminal No. 2 and ground. If battery voltage is present, go to next step. If battery voltage is not present, connect test light between CMP connector terminal No. 2 and ground. If test light comes on, check wiring between CMP connector terminal No. 2 and ECM connector terminal A21 for a short to voltage. If test light does not come on, reconnect CMP connector. If engine starts, problem was poor terminal contact. If engine does not start, replace CMP.
  8. Turn ignition off. Wait approximately 2 minutes. Disconnect CMP connector. Connect an DVOM between CMP connector terminal No. 2 and ground. If DVOM reads infinite resistance, go to next step. If DVOM reads approximately zero ohms, check wiring between CMP connector terminal No. 2 and ECM connector terminal A21 for a short circuit to ground.
  9. Turn ignition off. Disconnect CMP connector. Disconnect ECM connector. Ensure ECM connector terminals are clean and free of oxidation. Reconnect ECM. Connect an DVOM between CMP connector terminal No. 2 and ground. If DVOM reads 500-300 ohms, check for poor contact at ECM connector. If DVOM does not read 500-300 ohms, check wiring between CMP connector terminal No. 2 and ECM connector terminal A21 for an open circuit.
  10. If fault is intermittent, check CMP and ECM connectors for loose connection, contact resistance, or oxidation. Check wiring between CMP connector terminal No. 1 and ECM connector terminal A18 for an intermittent open circuit. Check wiring between CMP 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 CMP connector terminal No. 3 and ECM connector terminal A36 for an intermittent open circuit.

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 P0410/EFI 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 P0410/EFI 448 : PULSED SECONDARY AIR INJECTION SYSTEM (PAIR) PUMP FLOW FAULT.

  1. Connect scan tool. See «RETRIEVING & ERASING DTCs»(ref-15336-S41120021042000122900000) under SELF-DIAGNOSTIC SYSTEM. If signal is PERMANENT, go to next step. If signal is INTERMITTENT, check for an intermittent short to voltage in circuit between PAIR pump relay terminal No. 4 to ECM terminal B38. see scheme 19 Repair as necessary. After repairs, go to step 4.
  2. Turn ignition off. Disconnect PAIR pump relay. PAIR relay is located in main relay compartment, at right side rear of engine compartment. see scheme 7 Turn ignition on. Using test light connected to ground, probe relay base terminal No. 4. If test light illuminates, go to next step. If test light does not illuminate, replace PAIR pump relay. After repairs, go to step 4.
  3. Check for short to voltage in signal circuit between PAIR pump relay terminal No. 4 and ECM terminal B38. see scheme 19 Repair as needed. After repairs, go to next step.
  4. Reconnect all connectors and components. Turn ignition on. With scan tool in DIAGNOSTIC MODE, activate PAIR pump. See «DIAGNOSTIC FUNCTIONS»(ref-15336-S00009046172004090300000) under SELF-DIAGNOSTIC SYSTEM. A "clicking sound" should be heard from the relay and the PAIR pump should start. If PAIR pump starts, fault has been corrected. If pump does not start, repeat procedure, starting with step 1.
  1. Connect scan tool. See «RETRIEVING & ERASING DTCs»(ref-15336-S41120021042000122900000) under SELF-DIAGNOSTIC SYSTEM. If signal is PERMANENT, go to step 3. If signal is INTERMITTENT, go to next step. Check for an intermittent open and short to ground in circuit between PAIR pump relay terminal No. 4 and ECM terminal B38 circuit. see scheme 19 Repair as necessary. Check for intermittent open in circuit between PAIR pump relay terminal No. 2 and main relay No. 1 (2/32). Main relay is located at right side rear of engine compartment. see scheme 12 Repair as necessary. After repairs, go to step 10.
  2. Check for loose connection, contact resistance and oxidation in PAIR pump relay socket cavities and ECM harness connectors. Repair as necessary. After repairs, go to step 10.
  3. Using scan tool, check for following DTCs: DTC P0136/EFI 153, DTC P0137/EFI 153 & DTC P0138/EFI 153 DTC P0130/EFI 212, DTC P0131/EFI 212 & DTC P0132/EFI 212 DTC P0335/EFI 214 DTC P0412/EFI 447, DTC P0413/EFI 447 & DTC P0414/EFI 447 DTC P0135/EFI 521 DTC P0443/EFI 541, DTC P0444/EFI 541 & DTC P0445/EFI 541 DTC P0446/EFI 614 If any DTCs are stored in memory, go to next step. If no DTCs are stored in memory, go to step 6.
  4. Ensure fuse 11B/5 is okay. Fuse 11B/5 is located in main relay compartment, at right side rear of engine compartment. see scheme 12 If fuse is okay, go to next step. If fuse is not okay, check circuit for short to ground. Repair as necessary. After repairs, go to step 10.
  5. Turn ignition on. Remove fuse 11B/5. Using DVOM, measure voltage at left side terminal of fuse 11B/5. If voltage does not exists, check for an open in circuit between fuse 11B/5 and main relay No. 1 (2/32). Repair as necessary. After repairs, go to step 10. If voltage exists, check for an open in circuit between fuse 11B/5 and PAIR pump relay (2/53) terminal No. 2. Repair as necessary. After repairs, go to step 10.
  6. Turn ignition off. Disconnect PAIR pump relay from relay base. PAIR pump relay is located in main relay compartment, at right side rear of engine compartment. see scheme 12 Turn ignition on. Using DVOM, measure voltage at relay base terminal No. 2. If voltage exists, go to next step. If voltage does not exist, check for an open in circuit between fuse 11B/5 and PAIR pump relay (2/53) terminal No. 2. Repair as necessary. After repairs, go to step 10.
  7. Turn ignition off. Using DVOM, measure resistance between ground and relay base terminal No. 4. Resistance should be infinite. If resistance is as specified, go to next step. If resistance is not as specified, check for short to ground in circuit between PAIR pump relay terminal No. 4 and ECM terminal B38. see scheme 19 Repair as necessary. After repairs, go to step 10.
  8. Turn ignition off. Connect Volvo test box. See «CONNECTING VOLVO TEST BOX (981 3190)»(ref-15336-S00031993592004090900000). Using DVOM, measure resistance between test box terminal No. 38 (B38) and PAIR relay base terminal No. 4. Resistance should be approximately zero ohms. If resistance is as specified, go to next step. If resistance is not as specified, check for an open in signal circuit between PAIR pump relay terminal No. 4 and ECM terminal B38. Repair as necessary. After repairs, go to step 10.
  9. Turn ignition off. Connect PAIR pump relay. Turn ignition on. Using scan tool in DIAGNOSTIC MODE, activate PAIR pump relay. See «DIAGNOSTIC FUNCTIONS»(ref-15336-S00009046172004090300000) under SELF-DIAGNOSTIC SYSTEM. If PAIR pump starts, DTC was caused by loose connections in PAIR pump relay harness connector. Check connectors for contact resistance and oxidation. Repair as necessary. After repairs go to next step. If PAIR does not start, replace PAIR pump relay. After repairs, go to next step.
  10. Turn ignition on. Using scan tool in DIAGNOSTIC MODE, activate PAIR pump. A "clicking sound" should be heard from the relay and the PAIR pump should start. If PAIR pump starts, fault has been corrected. If pump does not start, repeat procedure, starting with step 1.
  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. 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, 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 exhaust system. Repair as necessary. If air does escape from PAIR valve outlet, replace PAIR valve.

Diagnosis Procedure

  1. Check status message on scan tool. If status message is PERMANENT FAULT, LEAKAGE, go to next step. If status message is PERMANENT FAULT, FLOW TOO LOW, go step 4 . If status message is INTERMITTENT FAULT, LEAKAGE, 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 13 .
  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 PERMANENT FAULT, FLOW TOO LOW, turn ignition on. Using scan tool, activate PAIR pump. If a clicking sound is heard from relay and PAIR pump starts, go to step 7 . If a clicking sound is not heard from relay and PAIR pump does not start, turn ignition off. Disconnect PAIR pump relay connector "C". Measure voltage between PAIR pump relay connector "C" terminal No. 2 and ground. Turn ignition on. Using scan tool, activate PAIR pump. If voltage varies between 0-12 volts with a 3-second interval, go to next step. If voltage does not vary between 0-12 volts with a 3-second interval, replace PAIR pump relay
  5. Turn ignition off. Connect DVOM between PAIR pump connector "C" terminal No. 2 and ground. If DVOM does not read .5-2 ohms, go to next step. If DVOM does read .5-2 ohms, replace PAIR pump.
  6. Check PAIR pump ground for contact resistance or poor terminal contact. Repair as necessary. Connect DVOM between PAIR pump connector terminal No. 2 and ground. If DVOM reads .5-2 ohms, DTC was caused by poor contact at PAIR pump ground. If DVOM does not read .5-2 ohms, replace PAIR pump.
  7. 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 next step. If air escapes from PAIR valve outlet when pump is operating, go to step 10 .
  8. Turn ignition off. Carefully disconnect PAIR hose from PAIR valve. Turn ignition on. Using scan tool, activate PAIR pump. If air does not escape from end of hose when pump is running, go to next step. If air escapes from end of hose when pump is running, replace PAIR valve.
  9. Turn ignition off. Ensure hose between PAIR pump and PAIR valve is not blocked or leaking. Ensure hose to PAIR pump is not blocked. Repair as necessary. If hoses are okay, replace PAIR pump.
  10. 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 approximately 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.
  11. 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.
  12. 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.
  13. 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.
  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 7 .
  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, turn ignition off. Disconnect solenoid valve connector. Turn ignition on. Measure voltage between solenoid valve connector terminal No. 1 and ground. If battery voltage is present, go to next step. If battery voltage is not present, check wiring between solenoid valve terminal No. 1 and main relay for an open circuit.
  5. Turn ignition off. Connect DVOM between solenoid valve terminals No. 1 and 2. If DVOM reads 30-33 ohms, go to next step. If DVOM does not read 30-33 ohms, replace solenoid valve.
  6. Connect test box to ECM connector. Connect DVOM between test box pin No. 37 and solenoid valve connector terminal No. 2. If DVOM reads approximately zero ohms, DTC is caused by poor contact in ECM and/or solenoid valve connector. If DVOM does not read approximately zero ohms, check for open circuit in wiring between solenoid valve terminal No. 2 and ECM connector terminal A37.
  7. 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.
  1. May result in poor performance
  1. Check for other DTCs. If any DTC for misfiring is stored (DTCs 451, 452, 453, 454, 455, 543, 551, 552, 553, 554, 555 or 545) perform that testing first. If DTCs 435 or 436 are stored, perform testing for that DTC first. If none of the above DTCs are stored, go to next step.
  2. Perform a compression check on all cylinders. See «PRELIMINARY INSPECTION & ADJUSTMENTS»(ref-15334-S07391999472000122900000) in BASIC TESTING article. Repair as necessary. If compression is okay, go to next step.
  3. 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.
  1. None

Start and run engine at idle. Remove hose between CP valve and EVAP canister. Start and run engine at idle. 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. Repair as necessary. If no faults can be found, retest system using new CP valve.

Note. Before beginning diagnosis, this DTC may be caused by filling the gas tank while engine is running, or not fully tightening the gas cap. See Technical Service Bulletin DIAGNOSING FAULT CODES EF-611, EFI-612 for a quick test for this condition.

  1. Connect scan tool. See «RETRIEVING & ERASING DTCs»(ref-15336-S41120021042000122900000) under SELF-DIAGNOSTIC SYSTEM. Check status message on Volvo Scan Tool (998-8686) or equivalent scan tool. If fault is PERMANENT, LARGE LEAK, go to step 3. If fault is INTERMITTENT, LARGE LEAK, go to next step.
  2. Ensure fuel tank filler cap is on properly and seal is intact. Check for leaks or pinched hoses and hose connections at EVAP canister and fuel tank. If problem is found, repair as necessary. After repairs, go to step 11.
  3. Ensure fuel filler cap seal is intact. Check all fuel lines, including EVAP canister, roll-over valve, fuel pressure regulator, and fuel tank hoses and hose connections. If fuel filler cap seal and fuel hoses are okay, go to next step. If problem is found, repair as necessary. After repairs, go to step 11.
  4. Start and idle engine. Disconnect hose at Canister Purge (CP) valve from EVAP canister. With scan tool in DIAGNOSTIC MODE, read CP valve value to determine if valve is activated. If vacuum exists when valve is activated, go to step 6. If vacuum does not exist when valve is activated, go to next step.
  5. Reconnect CP valve hose. Start and idle engine. Disconnect hose between CP valve and intake manifold. If vacuum exists, replace CP valve. If vacuum does not exist, check for blockage in hose between CP valve and intake manifold. Repair as necessary. After repairs, go to step 11.
  6. Turn ignition off. Reinstall CP valve hose. Disconnect EVAP canister hose from CP valve. Start and idle engine. With scan tool in DIAGNOSTIC MODE, read CP valve value to determine whether valve is operating. If vacuum exists when CP valve is activated, go to next step. If vacuum does not exist, check for restriction in hose between CP valve and EVAP canister. Repair or replace as necessary. After repairs, go to step 11.
  7. Ensure all EVAP canister inlets and outlets are airtight. If EVAP canister inlets and outlets are okay, replace EVAP canister. After repairs, go to step 11. If EVAP canister inlets and outlets are not airtight, check hose between fuel tank and EVAP canister. Repair or replace hose as necessary. If hose is okay, go to next step.
  8. Turn ignition off. Ensure hose from fuel tank to EVAP canister is connected. Clamp hose between EVAP canister shut-off valve and EVAP canister with a hose clamp. see scheme 26 Carefully disconnect EVAP canister hose from CP valve. Connect Pressure Gauge (999 5646) to hose and Pressure Regulator (999 5544) to pressure gauge. see scheme 27 Set pressure to one psi (.07 kg/cm 2 ). Open valve on pressure gauge. Let pressure build for 5 minutes, ensuring pressure does not increase beyond maximum of 1.4 psi (.09 kg/cm 2 ). Close valve. Pressure may drop.14-.18 psi (.009-.012 kg/cm 2 ) before stabilizing. Observe pressure. Wait 10 minutes.
  9. If pressure does not stabilize, go to next step. If pressure stabilizes, disconnect pressure gauge. Reconnect EVAP canister hose. Remove hose clamp from hose between EVAP canister shut-off valve and EVAP canister. Start and idle engine. With scan tool in DIAGNOSTIC MODE, read 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. After repairs, go to step 11. If hose and connectors are okay, replace EVAP canister shut-off valve. After repairs, go to step 11.
  10. Turn ignition off. Pressurize fuel tank as outlined in step 8. Spray soapy water on fuel tank, fuel hoses and other components. Observe fuel tank, fuel hoses and other components for air escaping (air escaping will form bubbles around any holes when sprayed with soapy water). Repair as necessary. After repairs, go to step 11.
  11. Turn ignition off. Reinstall all hoses and components. Erase DTCs. See «RETRIEVING & ERASING DTCs»(ref-15336-S41120021042000122900000) under SELF-DIAGNOSTIC SYSTEM. Start and run engine until it reaches an operating temperature of 158° F (70° C) or more. Turn A/C off. Place transmission in P or N. Idle engine. On scan tool, select and run LEAKAGE DIAGNOSTIC. Wait until diagnostic is complete (may take up to 2 minutes). Read DTC. If DTC does not recur, testing is complete. If DTC recurs, repeat test, starting in step 1.

Note. Before beginning diagnosis, this DTC may be caused by filling the gas tank while engine is running, or not fully tightening the gas cap. See Technical Service Bulletin DIAGNOSING FAULT CODES EF-611, EFI-612 for a quick test for this condition.

  1. Connect scan tool. See «RETRIEVING & ERASING DTCs»(ref-15336-S41120021042000122900000) under SELF-DIAGNOSTIC SYSTEM. Check status message on Volvo Scan Tool (998-8686). If fault is PERMANENT, SMALL LEAK, go to next step. If fault is INTERMITTENT, SMALL LEAK, ensure fuel filler cap seal is intact. Check all hoses and hose connections at EVAP canister and fuel tank are not leaking or pinched. Repair as necessary. After repairs, go to step 8.
  2. Ensure fuel filler cap seal is intact. Check all hoses and hose connections at EVAP canister, EVAP canister shut-off valve and fuel tank. If fuel filler cap seal and fuel hoses are okay, go to next step. If fuel filler cap seal and fuel hoses are not okay, repair as necessary. After repairs, go to step 8.
  3. Turn ignition off. Start and idle engine. With scan tool in DIAGNOSTIC MODE, open CP valve opens. Pressure in fuel tank should drop. If tank pressure drops, go to next step. If fuel tank pressure does not drop, go to step 7.
  4. Turn ignition off. Ensure hose from fuel tank to EVAP canister is connected. Clamp hose between EVAP canister shut-off valve and EVAP canister with a hose clamp. see scheme 26 Carefully disconnect EVAP canister hose from CP valve. Connect Pressure Gauge (999 5646) to hose and Pressure Regulator (999 5544) to pressure gauge. see scheme 27 Set pressure to one psi (.07 kg/cm 2 ). Open valve on pressure gauge. Let pressure build for 5 minutes, ensuring pressure does not increase beyond maximum of 1.4 psi (.09 kg/cm 2 ). Close valve. Pressure may drop 0.14-0.18 psi (.009-.012 kg/cm 2 ) before stabilizing. Observe pressure. Wait 10 minutes.
  5. If pressure does not stabilize, go to next step. If pressure stabilizes, check EVAP canister shut-off valve hose for airtightness, and check connectors. If hose is okay, replace EVAP canister shut-off valve. After repair, go to step 8. If hose is not okay, repair as necessary. After repairs, go to step 8.
  6. Turn ignition off. Carefully pressurize fuel tank system to one psi (.07 kg/cm 2 ). Open valve on pressure gauge. Check fuel tank system by spraying soapy water from EVAP canister to canister purge valve, and spray line with pressure regulator and roll-over valve to fuel tank. Check fuel tank system components, including filler pipe and fuel tank filler cap, for air escaping (air escaping will form bubbles around any holes when sprayed with soapy water). Repair as necessary. After repairs, go to step 8.
  7. Turn ignition off. Remove fuel tank pressure sensor. Remove hose with vacuum fitting. Check fitting and hoses for blockage. Repair or replace hose or fitting as necessary, and go to next step. If fitting and hoses are not blocked, replace fuel tank pressure sensor, and go to next step.
  8. Turn ignition off. Reinstall all hoses and components. Erase DTCs. See «RETRIEVING & ERASING DTCs»(ref-15336-S41120021042000122900000) under SELF-DIAGNOSTIC SYSTEM. Start and run engine until it reaches an operating temperature of 158° F (70° C) or more. Turn A/C off. Place Transmission in P or N. Idle engine. On scan tool, select and run LEAKAGE DIAGNOSTIC. Wait until diagnostic is complete (may take up to 2 minutes). Read DTC. If DTC recurs, repeat test, starting in step 1. If DTC does not recur, testing is complete.
  1. May result in poor performance
  2. May result in fuel odor
  3. May result in uneven idling
  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, go to step 3 . If fault is INTERMITTENT, SIGNAL TOO HIGH, go to step 7 . If fault is INTERMITTENT, SIGNAL TOO LOW, go to step 8 .
  2. Turn ignition off. Disconnect EVAP valve. Using DVOM connected to ground, probe EVAP valve connector terminals No. 1 and 2. If DVOM reads approximately 26 ohms, check wiring between EVAP valve connector terminal No. 2 and ECM connector terminal A39 for a short circuit to voltage. If DVOM does not read 26 ohms, retest using new EVAP valve.
  3. Turn ignition off. Disconnect EVAP valve. Turn ignition on. Measure voltage between EVAP valve connector terminal No. 1 and ground. If battery voltage is present, go to next step. If battery voltage is not present, check wiring between EVAP valve connector terminal No. 1 and main relay connector terminal No. 3 for an open circuit.
  4. Turn ignition off. Wait approximately 2 seconds. Disconnect EVAP valve. Using DVOM connected to ground, probe EVAP valve connector terminal No. 2. If DVOM reads 25,000-40,000 ohms, go to next step. If DVOM reads infinite resistance, go to step 6 . If DVOM reads approximately zero ohms, check wiring between EVAP valve connector terminal No. 2 and ECM connector terminal A39 for a short circuit to ground.
  5. Turn ignition off. Disconnect EVAP valve connector. Using DVOM connected to ground, probe EVAP valve connector terminals No. 1 and 2. If DVOM reads approximately 26 ohms, DTC is caused by poor contact in EVAP and/or ECM connector. Repair as necessary. If DVOM does not read approximately 26 ohms, retest using new EVAP valve.
  6. Turn ignition off. Disconnect EVAP valve connector. Disconnect ECM. Ensure ECM connector terminals are clean and make good terminal contact. Repair as necessary. Using DVOM connected to ground, probe EVAP valve connector terminal No. 2. If DVOM reads 25,000-40,000 ohms, DTC is caused by poor contact at ECM connector. If DVOM does not read 25-40 k/ohms, check wiring between EVAP valve connector terminal No. 2 and ECM connector terminal A39 for an open circuit.
  7. If fault is intermittent and signal is too high, check wiring between EVAP valve connector terminal No. 2 and ECM connector terminal A39 for an intermittent short circuit to voltage. Repair as necessary.
  8. If fault is intermittent and signal is too low, check EVAP valve and ECM connector for loose connection or contact resistance. Check wiring between EVAP valve connector terminal No. 1 and main relay connector terminal No. 3 for an intermittent open circuit. Also check wiring between EVAP valve connector terminal No. 2 and ECM connector terminal A39 for an intermittent open circuit or short circuit to ground.
  1. Connect scan tool. See «RETRIEVING & ERASING DTCs»(ref-15336-S41120021042000122900000) under SELF-DIAGNOSTIC SYSTEM. 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 the following and repair as necessary: Hose between EVAP canister and EVAP canister shut-off valve is not blocked or pinched. EVAP canister hose connection to EVAP canister shut-off valve is not blocked. EVAP canister shut-off valve and filter for dirt and deposits. With scan tool in DIAGNOSTIC MODE, check function of EVAP canister shut-off valve. After repairs, go to step 7 .
  2. Start and idle engine. Open fuel filler cap. With scan tool in DIAGNOSTIC MODE, observe fuel tank pressure value. If fuel tank pressure value is more than -.14 psi (-.009 kg/cm 2 ), go to next step. If fuel tank pressure value is less than -0.14 psi (-.009 kg/cm 2 ), remove fuel tank and replace fuel tank pressure sensor (located on top of fuel tank in front of fuel pump). See «FUEL TANK PRESSURE SENSOR»(ref-15342-S28491578422000122900000) under FUEL SYSTEM in REMOVE/INSTALL/OVERHAUL article. After repairs, go to step 7 .
  3. Disconnect hose between CP valve and EVAP canister at CP valve. Start and idle engine. With scan tool in DIAGNOSTIC MODE, check if EVAP valve is activated. Check for vacuum in EVAP valve hose. If vacuum does not exist when valve is not activated, go to next step. If vacuum exists when valve is not activated, replace CP valve. After repairs, go to step 7 .
  4. Turn ignition off. Ensure hose between EVAP canister and EVAP canister shut-off valve is not pinched or kinked. If hose is okay, carefully disconnect it from EVAP canister and EVAP shut-off valve and check hose for blockage. If hose is okay, go to next step. If hose is not okay, replace as necessary. After repairs, go to step 7 .
  5. Turn ignition off. Check hose between EVAP canister shut-off valve and canister filter for pinches or kinks. Repair as necessary. After repairs, go to step 7 . If there are no faults in hose, carefully disconnect it from EVAP canister shut-off valve. Ensure hose and filter are not blocked. If there are no faults, go to next step. If there are faults, repair as necessary. After repairs, go to step 7 .
  6. Turn ignition off. Carefully disconnect hose between EVAP canister hose and EVAP canister shut-off valve. Check EVAP canister shut-off valve connection to EVAP canister. If EVAP canister shut-off valve connection to EVAP canister is blocked, replace EVAP canister. After repair, go to next step. If EVAP canister shut-off valve connection to EVAP canister is not blocked, install new EVAP canister shut-off valve. After repair, go to next step.
  7. Turn ignition off. Reinstall all hoses and components. Erase DTCs. See «RETRIEVING & ERASING DTCs»(ref-15336-S41120021042000122900000) under SELF-DIAGNOSTIC SYSTEM. Run engine to operating temperature, 158° F (70° C) or more. Turn A/C off. Place Transmission in P or N. Idle engine. On scan tool, select and run LEAKAGE DIAGNOSTIC. Wait until diagnostic is complete (may take up to 2 minutes). Read DTC. If DTC recurs, repeat test, starting in step 1 . If DTC does not recur, testing is complete.
  1. Connect scan tool. See «RETRIEVING & ERASING DTCs»(ref-15336-S41120021042000122900000) under SELF-DIAGNOSTIC SYSTEM. If fault is PERMANENT, SIGNAL TOO HIGH, go to next step. If fault is INTERMITTENT, SIGNAL TOO HIGH, check for short to voltage in circuit between EVAP canister shut-off valve connector terminal No. 2 and ECM connector terminal B19. see scheme 19 Repair as necessary. After repairs, go to step 3.
  2. Turn ignition off. Disconnect EVAP canister shut-off valve harness connector. Turn ignition on. Using test light connected to ground, probe shut-off valve harness connector terminal No. 2. If test light does not come on, replace EVAP canister shut-off valve. After repairs, go to next step. If test light comes on, check for short to voltage in circuit between EVAP canister shut-off valve connector terminal No. 2 and ECM connector terminal B19. Repair as necessary. After repairs, go to next step.
  3. Turn ignition off. Connect EVAP canister shut-off valve and ECM harness connectors. Turn ignition on. With scan tool in DIAGNOSTIC MODE, activate EVAP canister shut-off valve. If components are working, testing is complete. If DTC recurs, repeat test, starting in step 1.
  1. Connect scan tool. See «RETRIEVING & ERASING DTCs»(ref-15336-S41120021042000122900000) under SELF-DIAGNOSTIC SYSTEM. If fault is PERMANENT, SIGNAL TOO LOW, go to next step. If fault is INTERMITTENT, SIGNAL TOO LOW, check for short to ground in circuit between EVAP canister shut-off valve terminal No. 2 and ECM connector terminal B19. Repair as necessary. After repairs, go to step 3.
  2. Check for short to ground in circuit between solenoid valve terminal No. 2 and ECM harness connector terminal A37. see scheme 19 Repair as necessary. After repairs, go to next step.
  3. Turn ignition off. Connect EVAP canister shut-off valve and ECM harness connectors. Turn ignition on. With scan tool in DIAGNOSTIC MODE, activate EVAP canister shut-off valve. If components are working, testing is complete. If DTC recurs, repeat test, starting in step 1.

Diagnosis (Signal Missing)

  1. Connect scan tool. See «RETRIEVING & ERASING DTCs»(ref-15336-S41120021042000122900000) under SELF-DIAGNOSTIC SYSTEM. If fault is PERMANENT, SIGNAL MISSING, go to next step. If fault is INTERMITTENT, SIGNAL MISSING, go to step 5.
  2. Turn ignition off. Disconnect EVAP canister shut-off valve harness connector. Turn ignition on. Using DVOM, measure voltage between ground and EVAP shut-off valve harness connector terminal No. 1. If voltage exist, go to next step. If voltage does not exist, check for an open in circuit between EVAP shut-off valve terminal No. 1 and main relay. Main relay is located at right side rear of engine compartment. see scheme 12 Repair as necessary. After repairs, go to step 6.
  3. Turn ignition off. Using DVOM, measure resistance between EVAP canister shut-off valve terminals No. 1 and 2. Resistance should be 14-20 ohms. If resistance is as specified, go to next step. If resistance is not as specified, replace EVAP canister shut-off valve. see scheme 11 After repairs, go to step 6.
  4. Turn ignition off. Connect test box. See «CONNECTING VOLVO TEST BOX (981 3190)»(ref-15336-S00031993592004090900000). Using DVOM, measure resistance between test box pin No. 19 (B19) and EVAP canister shut-off valve harness connector terminal No. 2. If resistance is as specified, DTC was caused by poor terminal contact at ECM or EVAP canister shut-off valve. Repair as necessary. After repairs, go to step 6. If resistance is not as specified, check for open in circuit between EVAP canister shut-off valve terminal No. 2 and ECM connector terminal B19. see scheme 19 Repair as necessary. After repairs, go to step 6.
  5. Check for loose connections, contact resistance or oxidation at EVAP canister shut-off valve and/or ECM connectors. Check for an intermittent open in circuit between EVAP canister shut-off valve terminal No. 1 and main relay terminal No. 3 (2/35). Check for an intermittent open in circuit between EVAP canister shut-off valve terminal No. 2 and ECM harness connector terminal B19. Repair as necessary. After repairs, go to step 6.
  6. Turn ignition off. Connect EVAP canister shut-off valve and ECM harness connectors. Turn ignition on. With scan tool in DIAGNOSTIC MODE, activate EVAP canister shut-off valve. If EVAP shut-off valve clicks, testing is complete. If DTC recurs, repeat test, starting in step 1.
  1. Connect scan tool. See «RETRIEVING & ERASING DTCs»(ref-15336-S41120021042000122900000) under SELF-DIAGNOSTIC SYSTEM. If signal is PERMANENT, go to next step. If signal is INTERMITTENT, check the following: Loose connection at fuel tank pressure sensor. Loose connection at ECM harness connectors. Loose connection at bulkhead connectors 24/2 and 24/4. Intermittent short in supply voltage in circuit between tank pressure sensor terminal No. 2 and ECM B31 via bulkhead connector 24/4 terminal No. E5. Intermittent short in supply voltage in bulkhead connector 24/2 terminal C6 circuit. Intermittent open in circuit between tank pressure sensor terminal No. 1 and ECM terminal B28 via bulkhead connector 24/4 terminal E6. Intermittent open in bulkhead connector 24/2 terminal C7 circuit. Repair as necessary. After repairs, go to step 7.
  2. Turn ignition off. Wait approximately 2 minutes. Disconnect fuel tank pressure sensor. see scheme 1 Using DVOM, measure resistance between ground and fuel tank pressure sensor harness connector terminal No. 1. If resistance reads approximately zero ohms, go to step 4. If resistance does not read approximately zero ohms, go to next step.
  3. Turn ignition off. Check for contact resistance and oxidation at bulkhead connector 24/4. see scheme 20 Ensure ECM is securely connected. Ensure bulkhead connector 24/4 is connected. Using DVOM, measure resistance at fuel tank pressure sensor harness connector terminal No. 1. Resistance should be approximately zero ohms. If resistance is within specification, go to step 7. If resistance is not within specification, check for an open in circuit between fuel tank pressure sensor terminal No. 2 and ECM terminal B28. see scheme 19 Repair as necessary. After repairs, go to step 7.
  4. Turn ignition on. Disconnect fuel tank pressure sensor harness connector. Using DVOM, measure voltage between ground and fuel tank pressure sensor harness connector terminal No. 2. Voltage should be 5-6 volts. If voltage is as specified, go to step 6. If voltage is less than specified, go to next step. If voltage is more than specified, check for short to voltage in circuit between fuel tank pressure sensor terminal No. 2 and ECM terminal B31. Repair as necessary. see scheme 19 After repairs, go to step 7.
  5. Turn ignition off. Disconnect fuel tank pressure sensor harness connector. Check for contact resistance and oxidation at ECM harness connector, and bulkhead connectors 24/2 and 24/4. see scheme 20 Repair as necessary. Ensure ECM is securely connected. Connect bulkhead connectors 24/2 and 24/4. Turn ignition on. Using DVOM, measure voltage between ground and fuel tank pressure sensor connector terminal No. 2. Voltage should be approximately 5 volts. If voltage is as specified, go to step 7. If voltage is not as specified, check for an open in signal circuit between fuel tank pressure sensor terminal No. 3 and ECM terminal B31. Repair as necessary. After repairs, go to step 7.
  6. Turn ignition off. Ensure fuel tank pressure sensor is connected. Start and idle engine for at least one minute. With scan tool in DIAGNOSTIC MODE, check DTC status message. If an INTERMITTENT fault is not displayed, replace fuel tank pressure sensor. After repairs, go to next step. If INTERMITTENT fault is displayed, DTC was caused by loose connection in fuel tank pressure sensor. Check for contact resistance and oxidation at fuel tank pressure sensor harness connector. Repair as necessary. After repairs, go to next step.
  7. Turn ignition off. reconnect all components. Start engine and idle. With scan tool in DIAGNOSTIC MODE, check DTC status message. If DTC is stored, DTC should have INTERMITTENT status. If DTC is INTERMITTENT, fault has been corrected. If DTC is not INTERMITTENT, repeat testing, starting with step 1.
  1. Connect scan tool. See «RETRIEVING & ERASING DTCs»(ref-15336-S41120021042000122900000) under SELF-DIAGNOSTIC SYSTEM. If signal is PERMANENT, go to next step. If signal is INTERMITTENT, check the following: Loose connections at fuel tank pressure sensor. Loose connections at ECM harness connectors. Loose connections at bulkhead connectors 24/2 and 24/4. Intermittent short in circuit between fuel tank pressure sensor terminal No. 2 and ECM terminal B31 via bulkhead connector 24/2 terminal E5. Intermittent short in bulkhead connector 24/2 terminal C6 circuit. Intermittent short in circuit between tank pressure sensor terminal No. 3 and ECM terminal B15 via bulkhead connector 24/4 terminal E4. Intermittent short in bulkhead connector 24/2 terminal C5 circuit. Intermittent short to ground in circuit between accelerometer terminal No. 1 and ECM terminal B1. Intermittent short to ground in circuit between A/C pressure sensor terminal No. 3 and ECM terminal B29. Repair as necessary. After repairs, go to step 10.
  2. Turn ignition off. Wait approximately 2 minutes. Disconnect fuel tank pressure sensor. Using DVOM, measure resistance between ground and fuel tank pressure sensor harness connector terminal No. 3. Resistance should be approximately 0.2-1.5 k/ohms. If resistance is as specified, go to step 7. If resistance is less than specified, go to next step. If resistance is more than specified, go to step 8.
  3. Turn ignition off. Disconnect accelerometer. Accelerometer is located in front of engine compartment. see scheme 7 Using DVOM, measure resistance between ground and fuel tank pressure sensor connector terminal No. 3. Resistance should be approximately 0.2-1.5 k/ohms. If resistance is as specified, replace accelerometer. After repairs, go to step 10. If resistance is not as specified, go to next step.
  4. Turn ignition off. Disconnect fuel tank pressure sensor, accelerometer and A/C pressure sensor harness connectors. Using DVOM, measure resistance between ground and fuel tank pressure sensor connector terminal No. 3. Resistance should be 0.2-1.5 k/ohms. If resistance is as specified, replace A/C pressure sensor. If resistance is not as specified, go to next step.
  5. Turn ignition off. Disconnect atmospheric pressure sensor harness connector. Atmospheric pressure sensor is located at left side of front engine compartment. see scheme 7 Using DVOM, measure resistance between ground and fuel tank pressure sensor connector terminal No. 3. Resistance should be 0.2-1.5 k/ohms. If resistance is as specified, replace atmospheric pressure sensor. If resistance is not as specified, go to next step.
  6. Fuel tank pressure sensor power supply is common to accelerometer and A/C pressure sensor. If a problem occurs in power supply, all 3 components will be affected. Check for an open circuit, or short to ground in circuits between following: Accelerometer Terminal No. 1 And ECM Terminal B1 A/C Pressure Sensor Terminal No. 3 And ECM Terminal B29 Fuel Tank Pressure Sensor Terminal No. 3 And ECM Terminal B15 Repair as necessary. After repairs, go to step 10.
  7. Turn ignition off. Disconnect fuel tank pressure sensor harness connector. Fuel tank pressure sensor is located on top of fuel tank. see scheme 1 Using DVOM, measure voltage between ground and fuel tank pressure sensor harness connector terminal No. 2. Voltage should be 5-6 volts. If voltage is within specification, replace fuel tank pressure sensor. After repairs, go to step 10. If voltage is not within specification, check for an open in signal circuit between fuel tank pressure sensor terminal No. 2 and ECM B31. Repair as necessary. After repairs, go to step 10.
  8. Turn ignition off. Check ECM harness connector and bulkhead connectors 24/2 and 24/4 for contact resistance and oxidation. Repair as necessary. Ensure ECM is securely connected. Ensure bulkhead connectors 24/2 and 24/4 are connected. Using DVOM, measure resistance between ground and fuel tank pressure sensor connector terminal No. 3. Resistance should be 0.2-1.5 k/ohms. If resistance is not within specification, go to next step. If resistance is within specification, system is okay. Go to step 10.
  9. Check for an open in circuit between fuel tank pressure sensor terminal No. 3 and ECM terminal B15. see scheme 19 Repair as necessary. After repairs, go to step 10.
  10. Turn ignition off. Reconnect all components. Start engine and idle. Using scan tool, read DTCs. If DTC P0452/EFI 621 is stored, DTC should have intermittent status. If signal is intermittent, fault was corrected. If signal is not intermittent, fault was not found. Repeat testing, starting with step 1.

Diagnosis (Signal Sporadic)

  1. Connect scan tool. See «RETRIEVING & ERASING DTCs»(ref-15336-S41120021042000122900000) under SELF-DIAGNOSTIC SYSTEM. If fault is PERMANENT, go to next step. If fault is INTERMITTENT check the following: Fuel tank pressure sensor and ECM connectors for loose connections. Intermittent short to ground in circuit between fuel tank pressure sensor terminal No. 3 and ECM terminal B15. Intermittent open in circuit between fuel tank pressure sensor terminal No. 2 and ECM terminal B3. Intermittent open in circuit between fuel tank pressure sensor terminal No. 1 and ECM terminal B28. Fuel tank pressure sensor power supply is common to A/C pressure sensor, atmospheric pressure sensor and accelerometer power cables. If anything happens to any of the power supply, all four components will be affected. Intermittent short to supply voltage in circuit between A/C pressure sensor terminal No. 3 and ECM terminal B29. Intermittent short to supply voltage in circuit between atmospheric pressure sensor terminal No. 1 and ECM terminal B15. Intermittent short to supply voltage in circuit between accelerometer terminal No. 1 and ECM terminal B1. Repair as necessary. After repairs, go to step 8.
  2. Turn ignition off. Check for contact resistance and oxidation at fuel tank pressure sensor harness connector, ECM harness connector, and bulkhead connectors 24/2 and 24/4. Repair as necessary. Ensure fuel tank pressure sensor and ECM are connected. Start engine and idle. Wait at least 5 minutes. With scan tool in DIAGNOSTIC MODE, read off DTC. If DTC P0450/EFI 621 is stored, DTC should have an INTERMITTENT status. If status is INTERMITTENT, go to step 8. If status is not INTERMITTENT, go to next step.
  3. Check for loose connections at fuel tank pressure sensor and/or ECM harness connector. Check for an intermittent open in circuit between fuel tank pressure sensor terminal No. 3 to ECM terminal B15. see scheme 19 Check for an intermittent open in circuit between fuel tank pressure sensor terminal No. 2 and ECM terminal B31. Check for an intermittent open in circuit between fuel tank pressure sensor terminal No. 1 and ECM terminal B28.
  4. Check for intermittent short to supply voltage in following circuits: A/C Pressure Sensor Terminal No. 3 To ECM Terminal B29 Atmospheric Pressure Sensor Terminal No. 1 To ECM Terminal B15 Accelerometer Terminal No. 1 To ECM terminal B1 Reinstall all components. Start engine and let idle for 5 minutes. Using scan tool, read DTCs. If DTC P0450/EFI 621 is stored in memory, it should have an INTERMITTENT status. If status is not INTERMITTENT, go to next step. If status is INTERMITTENT, go to step 8.
  5. Turn ignition off. Ensure fuel tank pressure sensor harness connector is connected. Disconnect A/C pressure sensor. A/C pressure sensor is located at right front of engine compartment. see scheme 7 Start engine and let idle for 5 minutes. Using scan tool, read DTC. If DTC P0450/EFI 621 is stored in memory, DTC should have an INTERMITTENT status. If status is INTERMITTENT, replace A/C pressure sensor. After repairs go to step 8. If status is not INTERMITTENT, go to next step.
  6. Turn ignition off. Ensure fuel tank pressure sensor harness connector is connected. Ensure A/C pressure sensor is connected. Disconnect accelerometer. Accelerometer is located at front of engine compartment. see scheme 7 Start engine and let idle for 5 minutes. Using scan tool, read DTCs. If DTC P0450/EFI 621 is stored in memory, DTC should have an INTERMITTENT status. If status is INTERMITTENT, replace accelerometer. After repairs, go to step 8. If status is not INTERMITTENT, go to next step.
  7. Turn ignition off. Ensure fuel tank pressure sensor harness connector is connected. Ensure accelerometer harness connector is connected. Disconnect atmospheric pressure sensor harness connector. Start engine and let idle for 5 minutes. Using scan tool, read DTCs. If DTC P0450/EFI 621 is stored in memory, it should have an INTERMITTENT status. If status is INTERMITTENT, replace atmospheric pressure sensor. see scheme 7 After repairs, go to next step. If status is not INTERMITTENT, replace fuel tank pressure sensor. see scheme 19 After repairs, go to next step.
  8. Turn ignition off. Reconnect all connectors and components. Disconnect scan tool from VADIS station and use it in stand-alone mode. Test drive vehicle. Using scan tool, read DTCs. If DTC P0450/EFI 621 is stored in memory, DTC should have an INTERMITTENT status. If status is INTERMITTENT, fault was corrected. If status is not INTERMITTENT, fault was not found. Repeat test, starting in step 1.
  1. No reading on speedometer, depending on fault cause
  1. Idling speed too high or low
  1. If Volvo Scan Tool (998-8686) reads UPPER LIMIT, go to next step. If scan tool reads LOWER LIMIT, go to 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 DVOM between IAC connector terminals No. 1 and 3. If DVOM reads 18-28 ohms, go to next step. If DVOM 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 DVOM between IAC valve connector terminal No. 1 and 3. If DVOM reads 18-28 ohms, go to next step. If DVOM 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.
  1. Air conditioning (A/C) compressor not running
  1. Checking ground lead. Turn ignition off. Wait for approximately 150 seconds (cars with immobilizer 245 seconds). Disconnect the air conditioning (A/C) pressure sensor. Connect an ohmmeter between air conditioning (A/C) pressure sensor connector 1 and ground. The ohmmeter should read approximately 0 ohms. If ohmmeter reading is OK, go to step 3 . If reading is NOT OK, go to step 2 .
  2. Checking ECM connector. Turn ignition off. Air conditioning (A/C) pressure sensor disconnected. Check ECM connector for contact resistance and oxidation and repair as necessary. With ECM connected, connect an ohmmeter between air conditioning (A/C) pressure sensor connector 1 and ground. The ohmmeter should read approximately 0 ohms. If reading is OK, go to step 3 . If reading is NOT OK, check A/C pressure sensor signal wire to ECM terminal No. B28 for an open circuit. After repair, go to step 6 .
  3. Checking signal wire. Turn ignition on. Disconnect air conditioning (A/C) pressure sensor. Connect a voltmeter between air conditioning (A/C) pressure sensor connector 2 and ground. The voltmeter should read approximately 0 V. If reading is OK, go to step 4 . If reading is NOT OK, check signal wire between A/C pressure sensor terminal 2 and ECM terminal No. B9 for an short circuit to supply voltage. After repair, go to step 6 .
  4. Checking signal cable resistance. Turn ignition off. Disconnect air conditioning (A/C) pressure sensor. Connect an ohmmeter between air conditioning (A/C) pressure sensor connector 2 and ground. The ohmmeter should read approximately 10,000 ohms. If reading is OK, go to step 5 . If reading is NOT OK, check wire between A/C pressure sensor terminal 2 and ECM terminal No. B9 for an open circuit. After repair, go to step 6 .
  5. Checking the air conditioning (A/C) pressure sensor. Turn ignition off. Connect air conditioning (A/C) pressure sensor. Start the engine and idle it. Turn air conditioning (A/C) switch on. Turn blower fan on. Select Volvo Scan Tool, or aftermarket scan tool, to read off the value of the air conditioning (A/C) pressure sensor signal. Voltage should increase when the air conditioning (A/C) compressor starts. If reading is OK, cause of the DTC has been loose connections in the air conditioning (A/C) pressure sensor connector. Check connector for contact resistance and oxidation and remedy. Go to step 6 . If reading is NOT OK, replace air conditioning (A/C) pressure sensor. Go to step 6 .
  6. After carrying out the repair, check that the fault has been remedied. Turn ignition off. Air conditioning (A/C) pressure sensor and engine control module (ECM) should be connected. Start the engine and idle it. Air conditioning (A/C) switch on. Blower fan on. Wait until the A/C compressor has started. Select Volvo Scan Tool, or aftermarket scan tool, to read off DTCs. If EFI-225 is stored they should have intermittent status.
  1. Checking power cable Turn ignition off. Disconnect the air conditioning (A/C) pressure sensor. Turn ignition on. Connect a voltmeter between air conditioning (A/C) pressure sensor connector 3 and ground. The voltmeter should read 5V. If reading is OK, go to step 3 . If value is lower, go to step 5 . If value is higher, go to step 2 .
  2. Checking for short circuit. Air conditioning (A/C) pressure sensor power cable is connected inside the ECM to the fuel tank pressure sensor, atmospheric pressure sensor and accelerometer power cables. If anything happens to any of these cables all four will be affected. Check cables for a short circuit to supply voltage between: Accelerometer terminal 1 and ECM terminal No. B1 Air conditioning (A/C) pressure sensor terminal 3 and ECM terminal No. B29 Atmospheric pressure sensor terminal 1 and ECM terminal No. B29 Tank pressure sensor terminal 1 and ECM terminal No. B15 After repairs, go to step 11 .
  3. Checking signal cable resistance. Turn ignition off. Air conditioning (A/C) pressure sensor disconnected. Connect an ohmmeter between air conditioning (A/C) pressure sensor connector 2 and ground. The ohmmeter should read approximately 10,000 ohms. If reading is OK, go to step 4 . If reading is NOT OK, the cause of the DTC has been loose connections in the air conditioning (A/C) pressure sensor connector. Check connector for contact resistance and oxidation and remedy. After repairs, go to step 11 .
  4. Checking the air conditioning (A/C) pressure sensor. Turn ignition off. Connect air conditioning (A/C) pressure sensor. Start the engine and idle it. Turn air conditioning (A/C) switch on. Turn blower fan on. Select Volvo Scan Tool, or aftermarket scan tool, to read off the value of the air conditioning (A/C) pressure sensor signal. Voltage should increase when the air conditioning (A/C) compressor starts. If reading is NOT OK, try a new A/C pressure sensor. Go to step 11 . If reading is OK, the cause of the DTC has been loose connections in the air conditioning (A/C) pressure sensor connector. Check connector for contact resistance and oxidation and remedy. Go to step 11 .
  5. Checking power cable resistance to ground. Turn ignition off. Air conditioning (A/C) pressure sensor disconnected. Wait for approximately 150 seconds (cars with immobilizer 245 seconds). Connect an ohmmeter between air conditioning (A/C) pressure sensor connector 3 and ground. The ohmmeter should read approximately 200-1500 ohms. If value is lower, go to step 6 . If value is higher, go to step 10 .
  6. Checking accelerometer. Turn ignition off. Air conditioning (A/C) pressure sensor disconnected. Disconnect accelerometer. Connect an ohmmeter between air conditioning (A/C) pressure sensor connector 3 and ground. The ohmmeter should read about 200-1500 ohms. If reading is OK, try a new accelerometer. Go to step 11 . If reading is NOT OK, go to step 7 .
  7. Checking atmospheric pressure sensor. Turn ignition off. Air conditioning (A/C) pressure sensor and accelerometer disconnected. Disconnect atmospheric pressure sensor. Connect an ohmmeter between air conditioning (A/C) pressure sensor connector 3 and ground. The ohmmeter should read approximately 200-1500 ohms. If reading is OK, try a new atmospheric pressure sensor. Go to step 11 . If reading is not OK: Models With EVAP leak diagnostic: Go to step 8 . Models Without EVAP leak diagnostic: Go to step 9 .
  8. Checking fuel tank pressure sensor. Turn ignition off. Air conditioning (A/C) pressure sensor, accelerometer and atmospheric pressure sensor disconnected. Disconnect fuel tank pressure sensor. Connect an ohmmeter between air conditioning (A/C) pressure sensor connector 3 and ground. The ohmmeter should read approximately 200-1500 ohms. If reading is OK, try a new fuel tank pressure sensor. Go to step 11 . If reading is NOT OK, go to 9 .
  9. Checking for a short-circuit. The air conditioning (A/C) pressure sensor power cable is connected inside the ECM to the fuel tank pressure sensor, atmospheric pressure sensor and accelerometer power cables. If anything happens to any of these cables all four will be affected. Check cables for a short circuit to ground between: Accelerometer terminal 1 and ECM terminal No. B1 Air conditioning (A/C) pressure sensor terminal 3 and ECM terminal No. B29 Atmospheric pressure sensor terminal 1 and ECM terminal No. B29 Tank pressure sensor terminal 1 and ECM terminal No. B15 Go to step 11 .
  10. Checking ECM connector. Turn ignition off. Air conditioning (A/C) pressure sensor disconnected. Check ECM connector for contact resistance and oxidation and remedy. Check wiring and terminals. With ECM connected, connect an ohmmeter between air conditioning (A/C) pressure sensor connector 3 and ground. The ohmmeter should read approximately 200-1500 ohms. If reading is OK, DTC has been caused by loose connections in the ECM connector. Go to step 11 . If reading is NOT OK, check wire between air conditioning (A/C) pressure sensor terminal 3 and ECM terminal No. B29 for an open-circuit. Go to step 11 .
  11. Verification. After carrying out the repair, check that the fault has been remedied as follows: Turn ignition off. Air conditioning (A/C) pressure sensor and ECM connected. Start the engine and idle it. Air conditioning (A/C) switch on. Blower fan on. Wait until the air conditioning (A/C) compressor has started. Select Volvo Scan Tool, or aftermarket scan tool, to read off DTCs. If EFI-225 is stored it should have intermittent status.

Diagnosis (Faulty Signal, Permanent Fault)

  1. Ensure A/C system is functioning correctly. If A/C system is not operating correctly, repair as necessary. If A/C system is OK, try a new air conditioning (A/C) pressure sensor. Go to next step.
  2. Verification After carrying out the repair, check that the fault has been remedied as follows: Turn ignition off Air conditioning (A/C) pressure sensor and engine control module (ECM) connected Start the engine and idle it Air conditioning (A/C) switch on Blower fan on Wait until the air conditioning (A/C) compressor has started Select Volvo Scan Tool, or aftermarket scan tool, to read off DTCs. If EFI-225 is stored it should have intermittent status.
  1. Checking cables and terminals. Check air conditioning (A/C) pressure sensor and ECM connectors for loose connections and contact resistance and oxidation.
  2. Check cable between air conditioning (A/C) pressure sensor terminal 2 and ECM terminal No. B9 for an intermittent open-circuit and an intermittent short circuit to supply voltage.
  3. Check cable between air conditioning (A/C) pressure sensor terminal 1 and ECM terminal No. B28 for an intermittent short circuit to ground.

Checking cables and terminals.

Note. Atmospheric pressure sensor is used on turbocharged engines.

  1. Check air conditioning (A/C) pressure sensor and engine control module (ECM) connectors for loose connections and contact resistance and oxidation.
  2. Check cable between air conditioning (A/C) pressure sensor terminal 3 and ECM terminal No. B29 for an intermittent open-circuit and an intermittent short circuit to ground.
  3. Check cable between air conditioning (A/C) pressure sensor terminal 2 and ECM terminal No. B9 for an intermittent short circuit to ground.
  4. Check cables between accelerometer terminal 1 and ECM terminal No. B1, atmospheric pressure sensor terminal 1 and ECM terminal No. B29, and fuel tank pressure sensor terminal 1 and ECM terminal No. B15 for an intermittent short circuit to ground.

Diagnosis (Faulty Signal, Intermittent Fault)

Check cable between connector 24/15 terminal 9 and air conditioning (A/C) compressor for an intermittent open circuit and an intermittent short-circuit to ground. Connector 24/15 is a 10 or 14-pin connector located in the right front of the engine compartment.

  1. Air conditioning (A/C) compressor not running
  1. Checking ground lead. Turn ignition off. Wait for approximately 150 seconds (cars with immobilizer 245 seconds). Disconnect the air conditioning (A/C) pressure sensor. Connect an ohmmeter between air conditioning (A/C) pressure sensor connector 1 and ground. The ohmmeter should read approximately 0 ohms. If ohmmeter reading is OK, go to step 3 . If reading is NOT OK, go to step 2 .
  2. Checking ECM connector. Turn ignition off. Air conditioning (A/C) pressure sensor disconnected. Check ECM connector for contact resistance and oxidation and repair as necessary. With ECM connected, connect an ohmmeter between air conditioning (A/C) pressure sensor connector 1 and ground. The ohmmeter should read approximately 0 ohms. If reading is OK, go to step 3 . If reading is NOT OK, check A/C pressure sensor signal wire to ECM terminal No. B28 for an open circuit. After repair, go to step 6 .
  3. Checking signal wire. Turn ignition on. Disconnect air conditioning (A/C) pressure sensor. Connect a voltmeter between air conditioning (A/C) pressure sensor connector 2 and ground. The voltmeter should read approximately 0 V. If reading is OK, go to step 4 . If reading is NOT OK, check signal wire between A/C pressure sensor terminal 2 and ECM terminal No. B9 for an short circuit to supply voltage. After repair, go to step 6 .
  4. Checking signal cable resistance. Turn ignition off. Disconnect air conditioning (A/C) pressure sensor. Connect an ohmmeter between air conditioning (A/C) pressure sensor connector 2 and ground. The ohmmeter should read approximately 10,000 ohms. If reading is OK, go to step 5 . If reading is NOT OK, check wire between A/C pressure sensor terminal 2 and ECM terminal No. B9 for an open circuit. After repair, go to step 6 .
  5. Checking the air conditioning (A/C) pressure sensor. Turn ignition off. Connect air conditioning (A/C) pressure sensor. Start the engine and idle it. Turn air conditioning (A/C) switch on. Turn blower fan on. Select Volvo Scan Tool, or aftermarket scan tool, to read off the value of the air conditioning (A/C) pressure sensor signal. Voltage should increase when the air conditioning (A/C) compressor starts. If reading is OK, cause of the DTC has been loose connections in the air conditioning (A/C) pressure sensor connector. Check connector for contact resistance and oxidation and remedy. Go to step 6 . If reading is NOT OK, replace air conditioning (A/C) pressure sensor. Go to step 6 .
  6. After carrying out the repair, check that the fault has been remedied. Turn ignition off. Air conditioning (A/C) pressure sensor and ECM should be connected. Start the engine and idle it. Air conditioning (A/C) switch on. Blower fan on. Wait until the A/C compressor has started. Select Volvo Scan Tool, or aftermarket scan tool, to read off DTCs. If EFI-225 is stored they should have intermittent status.
  1. Checking power cable Turn ignition off. Disconnect the air conditioning (A/C) pressure sensor. Turn ignition on. Connect a voltmeter between air conditioning (A/C) pressure sensor connector 3 and ground. The voltmeter should read 5V. If reading is OK, go to step 2 . If value is lower, go to step 4 . If value is higher, A/C pressure sensor power cable is connected inside ECM to fuel tank pressure sensor and accelerometer power cables. If anything happens to any of these cables, all 3 will be affected. They should always be checked. Check cables for a short-circuit between: Accelerometer terminal 1 and ECM terminal No. B1 Air conditioning (A/C) pressure sensor terminal 3 and ECM terminal No. B29 Tank pressure sensor terminal 1 and ECM terminal B15 Then, go to step 9 .
  2. Checking signal cable resistance. Turn ignition off. Air conditioning (A/C) pressure sensor disconnected. Connect an ohmmeter between air conditioning (A/C) pressure sensor connector 2 and ground. The ohmmeter should read approximately 10,000 ohms. If reading is OK, go to step 3 . If reading is incorrect, check cable between air conditioning (A/C) pressure sensor terminal 2 and ECM terminal No. B9 for a short-circuit to ground. Go to step 9 .
  3. Checking the air conditioning (A/C) pressure sensor. Turn ignition off. Connect air conditioning (A/C) pressure sensor. Start the engine and idle it. Turn air conditioning (A/C) switch on. Turn blower fan on. Select Volvo Scan Tool, or aftermarket scan tool, to read off the value of the air conditioning (A/C) pressure sensor signal. Voltage should increase when the air conditioning (A/C) compressor starts. If reading is NOT OK, try a new A/C pressure sensor. Go to step 9 . If reading is OK, the cause of the DTC has been loose connections in the air conditioning (A/C) pressure sensor connector. Check connector for contact resistance and oxidation and remedy. Go to step 9 .
  4. Checking power cable resistance to ground. Turn ignition off. Air conditioning (A/C) pressure sensor disconnected. Wait for approximately 150 seconds (cars with immobilizer 245 seconds). Connect an ohmmeter between air conditioning (A/C) pressure sensor connector 3 and ground. The ohmmeter should read approximately 200-1500 ohms. If reading is OK, go to step 5 . If reading is not OK, go to step 8 .
  5. Checking accelerometer. Turn ignition off. Air conditioning (A/C) pressure sensor disconnected. Disconnect accelerometer. Connect an ohmmeter between air conditioning (A/C) pressure sensor connector 3 and ground. The ohmmeter should read about 200-1500 ohms. If reading is OK, try a new accelerometer. Go to step 9 . If reading is NOT OK on vehicles with EVAP leak diagnostic, go to step 6 . If reading is NOT OK on vehicles without EVAP leak diagnostic, go to step 7 .
  6. Checking fuel tank pressure sensor. Turn ignition off. Disconnect air conditioning (A/C) pressure sensor and accelerometer. Disconnect fuel tank pressure sensor. Connect an ohmmeter between air conditioning (A/C) pressure sensor connector 3 and ground. The ohmmeter should read approximately 200-1500 ohms. If reading is OK, try a new fuel tank pressure sensor. Go to step 9 . If reading is NOT OK, go to 7 .
  7. Checking power cables. The A/C pressure sensor power cable is connected inside the ECM to the tank pressure sensor and accelerometer power cables. If anything happens to any of these cables, all 3 will be affected. Check cables for a short-circuit to ground between: Accelerometer terminal 1 and ECM terminal No. B1 Air conditioning (A/C) pressure sensor terminal 3 and ECM terminal No. B29 Tank pressure sensor terminal 1 and ECM terminal No. B15 Go to step 9 .
  8. Checking ECM connector. Turn ignition off. Air conditioning (A/C) pressure sensor disconnected. Check ECM connector for contact resistance and oxidation and remedy. With ECM connected, connect an ohmmeter between air conditioning (A/C) pressure sensor connector 3 and ground. The ohmmeter should read approximately 200-1500 ohms. If reading is OK, DTC was caused by loose connections in ECM connector. Go to step 9 . If reading is incorrect, check wire between air conditioning (A/C) pressure sensor connector 3 and ECM terminal No. B29 for an open circuit. Go to step 9
  9. Verification. After carrying out the repair, check that the fault has been remedied as follows: Turn ignition off. Air conditioning (A/C) pressure sensor and ECM connected. Start the engine and idle it. Air conditioning (A/C) switch on. Blower fan on. Wait until the air conditioning (A/C) compressor has started. Select Volvo Scan Tool, or aftermarket scan tool, to read off DTCs. If EFI-225 is stored it should have intermittent status.
  1. Engine does not start
  2. Engine cuts out

Diagnosis (Signal Missing, Permanent Fault

  1. Checking engine speed (RPM) sensor resistance. Turn ignition off. Disconnect the engine speed (RPM) sensor. Connect an ohmmeter between engine speed (RPM) sensor connector terminals 1 and 2 (sensor side). The ohmmeter should read 200-500 ohms depending on engine speed (RPM) sensor temperature. If reading is OK, go to step 2 . If reading is NOT OK, replace RPM sensor, then go to step 8 .
  2. Checking ground lead. Turn ignition off. Wait for approximately 150 seconds (cars with immobilizer 245 seconds). Disconnect Engine speed (RPM) sensor. Connect an ohmmeter between engine speed (RPM) sensor connector terminal 2 (ECM side) and ground. The ohmmeter should read approximately 0 ohms. If reading is OK, go to step 4 . If reading is NOT OK, go to step 3 .
  3. Checking ECM ground terminals. Turn ignition off. Engine speed (RPM) sensor disconnected. Check ECM connector and ECM ground terminals for contact resistance and oxidation and remedy, With ECM connected, connect an ohmmeter between engine speed (RPM) sensor connector terminal 2 (ECM side) and ground. The ohmmeter should read approximately 0 ohms. If reading is OK, go to step 4 . If reading is incorrect, go check wire between engine speed (RPM) sensor connector terminal 2 and ECM terminal No. A6 for an open circuit. After repairs, go to step 8 .
  4. Checking signal cable resistance to ground. Turn ignition off. Engine speed (RPM) sensor disconnected. Connect an ohmmeter between engine speed (RPM) sensor connector terminals 1 and 2 (ECM side). The ohmmeter should read 15,000-25,000 ohms. If reading is OK, go to step 6 . If value is higher, go to step 5 . If value is lower, check wire between engine speed (RPM) sensor connector terminals 1 and ECM terminal No. A20 for a short circuit to ground. After repairs, go to step 8 .
  5. Checking ECM connector. Turn ignition off. Engine speed (RPM) sensor disconnected. Disconnect ECM. Check ECM connector for contact resistance and oxidation and remedy. Connect ECM connector. Connect an ohmmeter between engine speed (RPM) sensor connector terminals 1 and 2 (engine control module (ECM) side). The ohmmeter should read 15,000-25,000 ohms. If reading is OK, DTC was caused by contact resistance at ECM. Go to step 8 . If reading is incorrect, check wire between engine speed (RPM) sensor terminal 1 ECM terminal No. A20 for an open circuit. After repairs, go to step 8 .
  6. Checking for a short circuit to supply voltage in signal cable. Turn ignition on. Engine speed (RPM) sensor disconnected. Connect a voltmeter between engine speed (RPM) sensor connector terminal 1 and 2 (ECM). The voltmeter should read 1-2 V. If reading is OK, go to step 7 . If reading is incorrect, check wire between engine speed (RPM) sensor terminal 1 and ECM terminal A20 for a short circuit to supply voltage. After repairs, go to step 8 .
  7. Checking ECM connector. Turn ignition off. Check engine speed (RPM) sensor connector for contact resistance and oxidation and remedy. Connect engine speed (RPM) sensor. Try to start the engine. If engine starts, problem was loose connections in the engine speed (RPM) sensor and/or engine control module (ECM) connectors. Go to step 8 . If engine did NOT start, check carrier plate/flywheel for damage and scratches through the engine speed (RPM) sensor hole. If no faults are detected on the carrier plate/flywheel, try a new engine speed (RPM) sensor. Go to step 8 .
  8. After carrying out repairs, check that fault has been remedied. Turn off ignition. Reconnect all connectors. Install components. Try to start engine. If the engine starts, fault is corrected. If engine does not start, repeat diagnostic procedure. Go to step 1 .

Check cables and terminals as follows

  1. Check ECM and engine speed (RPM) sensor connectors for loose connections, contact resistance and oxidation.
  2. Check cable between engine speed (RPM) sensor terminal 2 and ECM terminal No. A6 for an intermittent open circuit.
  3. Check cable between engine speed (RPM) sensor terminal 1 and ECM terminal No. A20 for an intermittent short circuit to supply voltage.
  4. Check for an intermittent short circuit to ground.
  5. Check for an intermittent open circuit.
  1. None
  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. Measure battery voltage. If voltage is 12-15 volts, check wiring between battery and ECM connector terminal A27 for an open circuit. If voltage is not 12-15 volts, check charging system. See GENERATOR & REGULATOR article in ELECTRICAL section. If voltage is 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.
  1. None

Load test battery. Battery voltage should be at approximately 12.4 volts. If voltage is not within specification, check connections and generator. See GENERATOR & REGULATOR article in CHARGING SYSTEMS under ELECTRICAL.

Faulty Symptoms

  1. None

Substitute Value (Fault In Knock Control Circuit: Zero Test, Integrator Test)

  1. Ignition retarded for safety reasons
  1. If ECM detects a fault in ROM/EPROM or RAM memory circuits, ECM temperature sensor circuit, knock control circuit, or ECT sensor circuit's NTC coupling, DTC 112 is set. If DTCs 432 and 513 are also present, go to testing for those DTCs. If these DTCs are not present, go to next step.
  2. If fault is permanent and signal is faulty, replace ECM. If fault is intermittent and signal is faulty, erase DTC. If DTC reoccurs, check ECM connector for good terminal contact. If terminal contact is okay, replace ECM.
  1. Can store misfire DTCs when travelling on an uneven road
  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 12 . If status message reads INTERMITTENT FAULT, SIGNAL TOO HIGH, go to step 13 . If status message reads INTERMITTENT FAULT, SIGNAL TOO LOW, go to step 15 .
  2. If PERMANENT FAULT, SIGNAL TOO HIGH is displayed on scan tool, turn ignition off. Wait approximately 2 minutes. Disconnect accelerometer connector. Measure voltage between accelerometer connector terminal No. 1 and ground. If voltage is 5 volts, go to next step. If voltage is less than 5 volts, go to step 6 . If voltage is more than 5 volts, note that accelerometer power lead is connected inside ECM to tank pressure, atmospheric, and A/C pressure sensor power leads. A problem in one wire will affect the other three. Repair as necessary.
  3. Turn ignition off. Disconnect accelerometer connector. Connect an DVOM between accelerometer connector terminal No. 2 and ground. If DVOM reads zero ohms, go to next step. If DVOM does not read zero ohms, disconnect ECM connector. Check ECM connector for poor terminal contact. Repair as necessary. Repeat test. If DVOM now reads approximately zero ohms, problem was poor contact at ECM connector. If DVOM does not read approximately 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. Measure voltage between accelerometer connector terminal No. 3 and ground. If voltage is approximately 5 volts, go to next step. If voltage reads more than 5 volts, check wiring between accelerometer connector terminal No. 3 and ECM connector terminal B32 for a short circuit to voltage. If voltage is less than 5 volts, turn ignition off. Check ECM connector for poor terminal contact. Repeat test. If voltage is now approximately 5 volts, problem was poor terminal contact. If voltage is not approximately 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 DVOM between accelerometer connector terminal No. 1 and ground. If DVOM reads approximately 200-1500 ohms, DTC was caused by poor terminal contact at ECM. If DVOM reads less than 200-1500 ohms, go to step 8 . If DVOM reads more than 200-1500 ohms, go to next step.
  7. Check ECM connector for poor terminal contact. Repair as necessary. Connect DVOM between accelerometer connector terminal No. 1 and ground. If DVOM reads approximately 200-1500 ohms, DTC was caused by poor ECM connection. If DVOM does not read 200-1500 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 DVOM between accelerometer connector terminal No. 1 and ground. If DVOM reads 200-1500 ohms, replace A/C pressure sensor. If DVOM does not read 200-1500 ohms, go to next step.
  9. Turn ignition off. Ensure accelerometer and A/C pressure sensor connectors are disconnected. Disconnect fuel tank pressure sensor. Connect DVOM between accelerometer connector terminal No. 1 and ground. If DVOM reads .2-1.5 k/ohms, replace pressure sensor. If DVOM does not read 200-1500 ohms, go to next step.
  10. Turn ignition off. Ensure accelerometer, A/C pressure sensor, fuel tank pressure sensor, and atmospheric pressure sensor are disconnected. Connect DVOM between accelerometer connector terminal No. 1 and ground. If DVOM reads 200-1500 ohms, replace atmospheric pressure sensor. If DVOM does not read 200-1500 ohms, go to next step.
  11. Accelerometer power lead is connected inside ECM to tank pressure sensor, atmospheric pressure sensor, and A/C pressure sensor power leads. A problem with one lead will affect the other three. Check wiring between accelerometer terminal No. 1 and ECM connector terminal B1, A/C pressure sensor terminal No. 3 and ECM connector terminal B29, atmospheric pressure sensor terminal No. 1 and ECM connector terminal B29, and tank pressure sensor terminal No. 1 and ECM connector terminal B15. Repair as necessary.
  12. If fault is permanent and signal is too low, turn ignition off. Disconnect accelerometer. Turn ignition on. Measure voltage between accelerometer connector terminal No. 3 and ground. If voltage is approximately 5 volts, retest using new accelerometer. If voltage is not approximately 5 volts, check wiring between accelerometer connector terminal No. 3 and ECM connector terminal B32 for a short circuit to ground.
  13. 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.
  14. Also check for an intermittent short circuit to ground in wiring between fuel tank pressure sensor terminal No. 1 and ECM connector terminal B15, atmospheric pressure sensor terminal No. 1 and ECM connector terminal B29, and A/C pressure sensor connector terminal No. 3 and ECM connector terminal B29.
  15. 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.
  1. None
  1. Check for other DTCs. If DTC 514 is stored, perform testing for that DTC first. If DTC 514 is not stored, go to next step.
  2. Using Volvo Scan Tool (998-8686), use Diagnostic Test Mode (DTM) No. 3 to check if engine cooling fan is functioning and that air is being drawn into connector for ECM box air hose in fan shroud. If engine cooling fan operates, go to next step. If engine cooling fan does not operate, perform testing for DTC 514.
  3. Turn ignition on. Set blower switch at highest speed. Close dash vents. Check if there is a slight stream of air from ECM box air hose. If air is blowing from hose, ECM box is cooling okay. Erase DTC. If no air is coming from hose, ensure hoses and couplings are in place and not blocked. Repair as necessary.
  1. Idling speed low or high
  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. Measure voltage between ground and IAC valve connector terminal No. 3 (DTC 223) or terminal No. 1 (DTC 245). If voltage is less than one volt, replace valve. If voltage is more than one volt on DTC 223, check wiring between IAC valve connector terminal No. 3 and ECM connector terminal A11 for a short circuit to voltage. On DTC 245, if voltage is more than one volt, 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. Measure voltage between IAC valve connector terminal No. 2 and ground. If battery voltage is present, go to next step. If battery voltage is not present, 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 approximately 2 minutes. Disconnect IAC valve connector. Connect an DVOM between IAC valve connector terminals No. 1 and 3. If DVOM reads 20,000-40,000 ohms, go to next step. If DVOM reads infinite resistance, check wiring between IAC valve terminal No. 3 and ECM connector terminal A11 for a short to ground. Repair as necessary. If DVOM shows approximately 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 DVOM between IAC valve connector terminals No. 1 and 2, then between terminals No. 2 and 3. If DVOM reads 9-14 ohms in both cases, cause of DTC is poor contact in IAC valve connector. Repair as necessary. If DVOM does not read 9-14 ohms in both cases, retest 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 approximately 2 minutes. Disconnect IAC valve. Connect DVOM between ground and IAC valve connector terminal No. 3. If DVOM does not read 10,000-20,00 ohms, go to next step. If DVOM reads 10,000-20,00 ohms, measure resistance between IAC valve connector terminals No. 1 and 2, then between terminals No. 2 and 3. If DVOM reads 9-14 ohms in both cases, DTC was caused by poor terminal contact at IAC valve connector. If DVOM does not read 9-14 ohms, replace IAC valve.
  10. Check IAC valve connector terminals and ECM connector terminals for poor terminal contact. Repair as necessary. Repeat test. If DVOM now reads 10,000-20,00 ohms, problem was poor terminal contact. If DVOM does not read 10-20 k/ohms, check wiring between IAC valve terminal No. 3 and ECM connector terminal A11 for an open circuit.
  1. Engine may run unevenly depending on fault cause.
  2. Engine may not start, depending on fault cause.
  3. Automatic transmission may shift at wrong time depending on fault cause
  4. MIL may light when the ignition is switched on depending on fault cause
  5. Engine cooling fan high speed may not work depending on fault cause
  1. If fault is intermittent, go to step 7 If fault is permanent, attempt to start engine. If engine starts, go to next step. If engine does not start, go to step 5 .
  2. Turn ignition on. Using scan tool, activate engine cooling fan at high speed. If cooling fan comes on, go to next step. If cooling fan does not come on, turn ignition off. Disconnect cooling fan relay "B". Connect test light between cooling fan relay "B" terminal No. 2 and ground. If test light does not come on, replace relay. If text light comes on, check wire between relay "B" terminal No. 2 and ECM connector terminal A22 for a short to voltage.
  3. If vehicle is equipped with M/T, go to next step. If vehicle is equipped with A/T, connect test box to ECM connector and check ground connections. See SYSTEM/COMPONENT TESTS article. Connect ECM to test box. Turn ignition on. Connect test light between test box pins B28 and B12. If test light comes on, go to next step. If test light does not come on, check wiring between ECM connector B12 and Transmission Control Module (TCM) connector B12 for a short circuit to voltage.
  4. Connect test box to ECM connector and check ground connections. See SYSTEM/COMPONENT TESTS article. Connect ECM to test box. Turn ignition on. Measure voltage between test box pins No. 7 and 28. If voltage is 0-2 volts, go to 7 . If voltage is not 0-2 volts, check wiring between instrument cluster connector terminal B11 and ECM connector terminal B7 for a short circuit to voltage.
  5. Turn ignition on. Using scan tool, activate fuel pump. Fuel pump relay should operate and fuel pump should run. If relay operates, go to next step. If relay does not operate, turn ignition off. Disconnect fuel pump relay. Turn ignition on. Connect test light between fuel pump relay connector terminal No. 4 and ground. If test light does not come on, replace relay. If test light comes on, check wiring between fuel pump relay connector terminal No. 4 and ECM connector terminal B27 for a short circuit to voltage.
  6. Turn ignition off. Disconnect Ignition Discharge Module (IDM) connector. Turn ignition on. Connect test light between IDM connector terminal No. 4 and ground. If test light comes on, replace IDM. If test light does not come on, check wire between IDM connector terminal No. 4 and ECM connector terminal B11 for a short circuit to voltage.
  7. Problem is intermittent. Check wiring between IDM connector terminal No. 4 and ECM connector terminal B11 for an intermittent short circuit to voltage. Check wiring between fuel pump relay terminal No. 4 and ECM connector terminal B27 for an intermittent short circuit to voltage. Check wiring between Malfunction Indicator Light (MIL) connector terminal B11 and instrument cluster connector terminal B7 for an intermittent short circuit to voltage. Check wiring between ECM connector terminal B12 and TCM connector terminal B12 for an intermittent short circuit to voltage. Also check wiring between cooling fan relay connector terminal B2 and ECM connector terminal A22 for an intermittent short circuit to voltage.
  1. A/C does not work, depending on fault source
  1. Using scan tool, read off other DTCs. If DTC 445 is present, perform testing for that DTC first. If DTC 445 is not present, go to next step.
  2. Check status message on Volvo Scan Tool (998-8686). If scan tool indicates FAULTY SIGNAL, go to next step. If scan tool indicates FAULTY SIGNAL, INTERMITTENT FAULT, check for an intermittent short to voltage in wiring between A/C relay terminal No. 4 and ECM connector terminal B40. Repair as necessary.
  3. Connect test box to ECM connector. Reconnect ECM. Turn A/C on. Put blower fan on low speed. Start and idle engine. Measure voltage between test box pins No. 40 and 28. If voltage is not 0-2 volts, go to next step. If voltage is 0-2 volts, check for an intermittent short to voltage in wiring between A/C relay terminal No. 4 and ECM connector terminal B40. Repair as necessary.
  4. Turn ignition off. Disconnect A/C relay. Turn A/C on. Put blower fan on low speed. Start and idle engine. Measure voltage between test box pins No. 40 and 28. If voltage is 0-2 volts, replace A/C relay. If voltage is not 0-2 volts, check wiring for short circuit to voltage between A/C relay terminal No. 4 and ECM connector terminal B40.
  1. None
  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.
  1. May result in poor performance
  1. Using Volvo Scan Tool (998-8686), read off 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. Measure voltage between FC relay connector "B", terminal No. 1, and ground. If voltage is approximately 6 volts, retest using new FC relay. If voltage is not approximately 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. Measure voltage between FC relay connector "B" terminal No. 1 and ground. If voltage is approximately 6 volts, replace FC relay. If voltage is not approximately 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. Measure voltage between FC relay connector "A" and ground. If battery voltage is present, go to next step. If battery voltage is not present, check fusible link between starter motor and FC relay.
  5. Turn ignition off. Disconnect FC relay connector "A". Disconnect FC relay connector "B". Turn ignition on. Measure voltage between relay connector "B" terminal No. 1 and ground. If voltage is approximately 6 volts, go to next step. If voltage is not approximately 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. Measure voltage between relay connector "B" terminal No. 2 and ground. If voltage is approximately 3 volts, go to next step. If voltage is not approximately 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 FAULT, 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.

Varies depending on the DTC stored in the Automatic Transmission Control Module (TCM).

  1. Connect scan tool. See «RETRIEVING & ERASING DTCs»(ref-15336-S41120021042000122900000) under SELF-DIAGNOSTIC SYSTEM.
  2. Ensure ECM harness connector terminal B19 is empty. see scheme 19 Check ECM pin B19 and adjacent pins are not damaged. Repair as necessary.
  3. If fault was corrected, testing is complete. If fault still exists, repeat procedure, starting with step 1.

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