Engine Controls - Basic Testing: Other Volvo S70 I

Compression

Check engine mechanical condition using a compression gauge, vacuum gauge or engine analyzer. See engine analyzer manual for specific instructions.

COMPRESSION SPECIFICATIONS

Exhaust System Backpressure

1. Exhaust system can be checked using a vacuum or pressure gauge. Remove oxygen sensor or air injection check valve (if equipped).
2. Connect a 1-10 psi pressure gauge, and run engine at 2500 RPM. If exhaust system backpressure is greater than 2 psi, exhaust system or catalytic converter is plugged.
3. If using a vacuum gauge, connect vacuum gauge hose to intake manifold vacuum port and start engine. Observe vacuum gauge. Open throttle part way and hold steadily. If vacuum gauge reading slowly drops after stabilizing, exhaust system should be checked for a restriction.

FUEL SYSTEM

Note. For wire color and terminal identification, see appropriate WIRING DIAGRAM in WIRING DIAGRAMS article.

FUEL PRESSURE

1. Before disconnecting, cover fuel line connector using shop towel to absorb any fuel spray. Connect Fuel Pressure Gauge (5011) between fuel line and fuel rail. Seal free end of hose using Plug (5266) or use Fuel Drainage Unit (981 2270, 2273 and 2282).
2. Remove fuel pump relay. Connect a jumper wire between relay terminals No. 1 and 3. (Scheme 1) Turn ignition on. Fuel pump should start. Fuel filler cover can be removed to determine whether main pump is operating. Check fuel pressure. See «FUEL PRESSURE SPECIFICATIONS (C/S/V70)»(ref-15334-S04184464362004092400000) table. If pressure is not to specification, replace pressure sensor.
3. To check fuel system residual pressure, turn ignition off. Disconnect jumper wire between relay terminals. Reinstall fuel pump relay. System pressure should not drop below specification in less than 20 minutes. See «FUEL PRESSURE SPECIFICATIONS (C/S/V70)»(ref-15334-S04184464362004092400000) table. If pressure is not to specification, check injectors, connections, and fuel pump non-return valve or lines. Repair as necessary.

Scheme 1

FUEL PRESSURE SPECIFICATIONS (C/S/V70

Scheme 2

C70, S70 & V70

1. Turn ignition off. Remove fuse No. 2. Connect ammeter between fuse No. 2 terminals. Turn ignition on. Using scan tool, activate fuel pump. If amperage is 4-5 amps, fuel pump is okay. If amperage is not 4-5 amps, go to next step.
2. Turn ignition off. Leave ammeter connected to fuse No. 2 terminals. Remove fuse/relay unit cover. Remove fuel pump relay at position No. 103. Turn ignition on. Connect jumper wire between relay connector terminals No. 1 and 3. (Scheme 1) If amperage is not 4-5 amps, go to next step. If amperage is 4-5 amps, go to step 6.
3. Reinstall fuse No. 2. Turn ignition on. Connect voltmeter between fuel pump relay terminals No. 1 and ground. (Scheme 1) Turn ignition on. If voltmeter reads battery voltage, go to next step. If voltmeter does not read battery voltage, check fuses and wiring.
4. Turn ignition off. Disconnect 2-pin fuel pump connector in trunk. Connect ohmmeter between relay side of fuel pump connector terminal No. 2 and ground. (Scheme 2) If about zero ohms are present, go to next step. If about zero ohms are not present, check connector terminals for poor terminal contact.
5. Connect ohmmeter between fuel pump side of fuel pump connector terminals No. 1 and 2. (Scheme 2) If about 0.5-2 ohms are present, check wiring between fuel pump relay terminals No. 1 and 3 for an open circuit.
6. Turn ignition off. Ensure fuel pump relay is disconnected. Connect ohmmeter between relay base terminal No. 2 and ground. If about zero ohms are present, go to next step. If about zero ohms are not present, check for terminal contact in relay ground circuit. If relay ground circuit is okay, check wiring between fuel pump relay terminal No. 2 and ground.
7. Turn ignition on. Ensure fuel pump relay is disconnected. Connect voltmeter between relay base terminal No. 4 and ground. If about 4-5 volts are present, go to next step. If greater than about 4-5 volts are present, check wiring between relay terminal No. 4 and ECM terminal B27 for a short circuit to ground. If less than about 4-5 volts are present, disconnect ECM. Connect ohmmeter between relay base terminal No. 4 and ground. If infinite resistance is present, check for open circuit in wiring between fuel pump relay terminal No. 4 and ECM connector terminal B27. If infinite resistance is not present, check for short circuit in wiring between relay base terminal No. 4 and ECM connector terminal B27.
8. Turn ignition off. Reinstall fuel pump relay. Reconnect ECM and fuel pump. Attempt to start engine. If engine does not start, replace fuel pump relay. If engine does start, problem was poor contact in ECM, fuel pump, or fuel pump relay connection.

Scheme 3

Scheme 4

1. Turn ignition off. Remove fuse No. 1 from central electrical unit located in left side of engine compartment. (Scheme 3) Turn ignition on. Lightly squeeze hose connected to fuel pressure regulator and reinstall fuse. If fuel pump operates for a few seconds after fuse is reinstalled, fuel pump is okay. Check ignition system. See «IGNITION CHECKS»(ref-15334-S39544825452000122900000). If fuel pump does not operate, go to next step.
2. Access fuse/relay box on left side of instrument panel. Remove fuel pump relay from position No. 2. Connect jumper wire between relay base terminals No. 1 and 3. (Scheme 1) Turn ignition on. Lightly squeeze hose connected to fuel pressure regulator and reinstall fuse. If fuel pump operates for a few seconds after fuse is reinstalled, go to step 6). If fuel pump does not operate, go to next step.
3. Turn ignition off. Ensure fuel pump relay is removed. Turn ignition on. Connect voltmeter between relay base terminal No. 1 and ground. (Scheme 1) If battery voltage is present, go to next step. If battery voltage is not present, check fuse No. 4. If fuse is okay, check voltage supply to fuse. Repair as necessary.
4. Turn ignition off. Disconnect fuel pump 4-pin connector located in luggage compartment. Connect ohmmeter between relay side of fuel pump connector terminal No. 4 and ground. (Scheme 4) If about zero ohms are present, go to next step. If about zero ohms are not present, check fuel pump connector terminals and ground at left seat support for poor terminal contact. Repair as necessary. Repeat resistance check. If reading is now okay, source of fault was poor terminal contact. If reading is still not okay, check for open circuit in wiring between fuel pump connector terminal No. 4 and ground, and at ground connection at left seat support. Repair as necessary.
5. Connect ohmmeter between fuel pump connector terminals No. 1 and 4. (Scheme 4) If about 0.5-2 ohms are present, check wiring between fuel pump relay terminal No. 3 and fuel pump terminal No. 1 for an open circuit. If about 0.5-2 ohms are not present, replace fuel pump.
6. Ensure ignition is on and fuel pump relay is removed. Connect voltmeter between relay base terminal No. 4 and ground. (Scheme 1) If about 2-5 volts are present, go to next step. If more than a bout 5 volts are present, check wiring between fuel pump relay terminal No. 4 and ECM terminal A40 for a short circuit to voltage. If less than 2 volts are present, turn ignition off. Connect ohmmeter between relay base terminal No. 4 and ground. If infinite resistance is present, check wiring between fuel pump relay terminal No. 4 and ECM terminal A40 for an open circuit. If infinite resistance is not present, check wiring between fuel pump relay terminal No. 4 and ECM terminal A40 for a short circuit to ground.
7. Ensure ignition is off. Reinstall fuel pump relay. Reconnect fuel pump connector. Attempt to start engine. If engine starts, cause of fault was poor contact in fuel pump relay or fuel pump connectors. Repair as necessary. If engine does not start, replace fuel pump relay.

1. Determine if fault is fuel or ignition. Check fuel pressure. See «FUEL PRESSURE»(ref-15334-S13516298022000122900000) under FUEL SYSTEM. If fuel pressure is not as specified, repair fuel system as necessary. If fuel pressure is as specified, fuel system is okay. Go to next step.
2. Using a high output spark tester, check for spark at end of one spark plug wire. If spark is not present, go to next step. If spark is present, remove and inspect all spark plugs. Replace spark plugs as necessary. Try to start engine. If engine starts, fault was due to spark plugs. If engine does not start, check for defective mass airflow sensor or engine coolant temperature sensor. See K - SENSOR OPERATING RANGE CHARTS article.
3. Turn ignition on. Select scrolling values on scan tool. Operate starter motor. Read off RPM. If RPM is 100-300 RPM during cranking, go to next step. If RPM is not 100-300 RPM, see ENGINE SPEED (RPM) SENSOR RESISTANCE table in K - SENSOR OPERATING RANGE CHARTS article.
4. Turn ignition off. Disconnect Ignition Discharge Module (IDM) connector. Turn ignition on. Connect voltmeter between IDM connector terminal No. 3 and ground. (Scheme 5) If battery voltage is present, go to next step. If battery voltage is not present, check fuse No. 4. Replace if necessary. If fuse is okay, check voltage supply to fuse.
5. Ensure ignition is off. Wait about 2 minutes. Disconnect IDM module connector. Connect ohmmeter between IDM connector terminal No. 1 and ground. (Scheme 5) If about zero ohms are present, go to next step. If about zero ohms are not present, check IDM connector ground terminal for poor terminal contact. Repair as necessary. Repeat test. If zero ohms are still not present, check for open circuit in wiring between IDM terminal No. 1 and ground.
6. Turn ignition on. Disconnect IDM module connector. Connect multimeter between IDM module connector terminal No. 4 and ground. (Scheme 5) Set multimeter to measure frequency. Operate starter motor. If frequency is 8-10 Hz when engine is cranked, go to step 9). If frequency is not 8-10 Hz when engine is cranked, go to next step.
7. Connect voltmeter between IDM connector terminal No. 4 and ground. (Scheme 5) If voltmeter reads 0-1 volt, go to next step. If voltmeter does not read 0-1 volt, check for short circuit to voltage in wiring between IDM terminal No. 4 and ECM terminal B11.
8. Turn ignition off. Wait about 2 minutes. Disconnect IDM module and ECM connectors. Connect ohmmeter between ground and IDM connector terminal No. 4. (Scheme 5) If infinite resistance is present, check for open circuit in wiring between IDM terminal No. 4 and ECM terminal B11. If infinite resistance is not present, check for short circuit to ground in wire between IDM terminal No. 4 and ECM terminal B11.
9. Turn ignition off. Reconnect IDM module connector. Turn ignition on. Disconnect ignition coil wire from distributor cap. Hold end of wire about 1/4 inch from ground. Operate starter motor. If a spark occurs, check rotor, distributor cap, and spark plugs. Replace as necessary. If a spark does not occur, replace IDM.

Scheme 5

Scheme 6

Scheme 7

1. Determine if fault is fuel or ignition. If fault is fuel related, go to «FUEL SYSTEM»(ref-15334-S40651218142000122900000). If fault is ignition, go to next step.
2. Disconnect one spark plug connector. Check for spark. If spark is present, go to step 8). If spark is not present, install scan tool to Data Link Connector (DLC) and check RPM signal while cranking engine. If engine speed is zero RPM, check RPM sensor circuit. If circuit is okay, replace RPM sensor. If engine speed is 100-300 RPM, go to next step.
3. Ensure ignition is off. Remove fuel pump relay from position No. 2 in relay/fuse box on left side of instrument panel. Connect jumper wire between relay base terminals No. 1 and 5. (Scheme 1) Turn ignition on. Connect voltmeter between ground and cylinder No. 1 test terminal at rear of engine. (Scheme 6) If battery voltage is not present, go to next step. If battery voltage is present, check Ignition Discharge Module (IDM) ground terminal No. 4 for poor connection. (Scheme 7)
4. Ensure ignition is off. Access fuse/relay box in left side of engine compartment. Remove ignition relay located in fuse/relay box position "J". (Scheme 2) Connect ohmmeter between relay base terminal No. 4 and ground. (Scheme 8) If about zero ohms are present, go to next step. If about zero ohms are not present, check ignition relay terminals for poor terminal contact. Repair as necessary. Repeat resistance check. If resistance is now to specification, source of fault was poor contact in relay ground. If resistance is not to specification, check for an open circuit in wiring between ignition relay terminal No. 4 and terminal block in fuse/relay block.
5. Turn ignition on. Ensure ignition relay is disconnected. Connect voltmeter between relay base terminals No. 1 and 4. (Scheme 8) If battery voltage is present, go to next step. If battery voltage is not present, check voltage supply to fuse No. 7. If voltage supply is okay, check for open circuit in wiring between fuse No. 7 and ignition relay terminal No. 1. If voltage supply is not okay, check for open circuit in wiring between fuse No. 7 and main relay terminal No. 3. See appropriate wiring diagram in WIRING DIAGRAMS article.
6. Ensure ignition is on. Ensure ignition relay is disconnected. Connect jumper wire between relay base terminals No. 1 and 5. (Scheme 8) Check voltage between relay base terminals No. 2 and ground. If battery voltage is present, go to next step. If battery voltage is not present, check wiring between ignition relay terminal No. 2 and fuel pump relay terminal No. 5. Fuel pump relay is located in position No. 2 of fuse/relay box on left side of instrument panel.
7. Turn ignition on. Ensure ignition relay is disconnected. Connect jumper wire between ignition relay base terminals No. 1 and 5. Reconnect ignition relay far enough to allow voltage readings to be taken on relay pins. Check voltage supply to ignition relay. If battery voltage is present, check for open circuit in wiring between ignition relay terminal No. 3 and ignition coil(s) terminal No. 2. See appropriate wiring diagram in WIRING DIAGRAMS article. If battery voltage is not present, replace ignition relay.
8. If spark was present in step 2), replace all spark plugs. Attempt to start engine. If engine starts, system is okay. If engine still does not start, go to next step.
9. Connect scan tool. Turn ignition on. Crank starter motor. Read off engine load signal. If reading is about 0.4-0.6 volt, go to next step. If reading is not about 0.4-0.6 volt, check Mass Airflow (MAF) sensor. See K - SENSOR OPERATING RANGE CHARTS article.
10. Turn ignition on. Using scan tool, go into scrolling values. Connect Multimeter (999 6525 ) with Temperature Box (999 5281 ) and Engine Coolant Temperature (ECT) Sensor (999 5282 ). Using pliers, squeeze hose between radiator and thermostat, bend down carefully, and remove it from thermostat housing. Put ECT sensor into thermostat housing. Reinstall hose. Ensure sensor reaches all the way down to thermostat. Read coolant temperature on multimeter. WARNING: Coolant may be very hot.
11. Using scan tool, read off coolant temperature. Reinstall hose. If scan tool displays correct coolant temperature, go to next step. If scan tool does not display correct coolant temperature, check ECT sensor. See K - SENSOR OPERATING RANGE CHARTS article.
12. Turn ignition off. If not done previously, check fuel and residual pressure. Go to «FUEL PRESSURE»(ref-15334-S13516298022000122900000) under FUEL SYSTEM. If fuel pressure is okay, go to next step.
13. Connect breakout box to ECM. (Scheme 9) Check all signals to and from ECM. See PIN VOLTAGE CHART S article. Repair circuits as necessary. If circuits are okay, replace ECM.

Scheme 8

Scheme 9

IDLE SPEED & IGNITION TIMING

See IDLE SPEED & CO LEVEL and IGNITION TIMING tables. Idle speed is not adjustable.

IDLE SPEED & CO LEVEL (1)

IGNITION TIMING (Degrees BTDC @ RPM)

SUMMARY

If no faults were found while performing BASIC DIAGNOSTIC PROCEDURES, proceed to appropriate TESTS W/CODES article. If no hard codes are found in self-diagnostics, proceed to TESTS W/O CODES article for diagnosis by symptom (i.e., ROUGH IDLE, NO START, etc.) or intermittent diagnostic procedures.