Part 3

Faulty signal (Continued)

Checking cable resistance

- Ignition off.
- Disconnect control module.
- Vacuum pump disconnected.
Connect an ohmmeter between vacuum pump connector terminal 2 and control module connector terminal 7S.

The ohmmeter should read approx. 0 ohms.

OK - Checking the vacuum pump

Not OK - Checking for an open-circuit

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Checking for contact resistance and oxidation

- Ignition off.
- Check control module connector and vacuum pump connector for contact resistance and oxidation and remedy according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault and loose connections according to Checking wiring and terminals. Intermittent faults Checking Wiring and Terminals. Intermittent Faults.

Continue - Verification, vacuum pump

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Checking for an open-circuit

- Ignition off.

- Check cable between vacuum pump connector terminal 2 and control module connector terminal 7S for an open-circuit according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.

Continue - Verification, vacuum pump

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Checking the vacuum pump

- Ignition off.
- Vacuum pump disconnected.
Temporarily connect a cable between vacuum pump terminal 3 and battery positive terminal and a cable between vacuum pump terminal 2 and battery negative terminal. The vacuum pump should now start.

- Remove temporary cables.

Did the vacuum pump start?

Yes - Checking for contact resistance and oxidation

No - Replacing component

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Checking for contact resistance and oxidation

Continue - Verification, vacuum pump

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Replacing component

- Ignition off.
- Try a new vacuum pump according to Replacing vacuum pump and regulator Service and Repair.

Continue - Verification, vacuum pump

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Checking the brake valve

- Ignition off.
- Control module disconnected.
- Disconnect battery leads from the battery.
- Connect vacuum pump.
- Install battery shelf and battery
- Connect battery leads to battery.
- Ignition on.
- Connect the single cable between control module connector terminal 1S and terminal 7T.
- Connect the other cable with the double blade terminal to control module connector terminal 3S, connect one end of the cable to control module connector terminal 9S. Connect the other end of the cable to control module connector terminal 7S.
The vacuum pump should start and the vacuum servo should pull the throttle mechanism to wide open throttle (WOT).

- Stop the vacuum pump when the vacuum servo has fully contracted by disconnecting the cable connected to the control module connector terminal 7S.
- Depress brake pedal.

Does the brake valve let air into the system so that the vacuum servo releases?

Yes - Fault-tracing information

No - Brake valve adjustment

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Fault-tracing information
- The clutch valve is only fitted to cars with a manual transmission so the transmission type must be entered to continue testing.

Does the car have a manual transmission?

Yes - Checking the clutch valve

No - No Fault Found

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Brake valve adjustment

- Ignition off.
- Control module disconnected.
- Vacuum pump connected.
- Disconnect hose connectors so the vacuum servo releases.
- Press pedal so that it is not in contact with the valve.
- Pull piston out as far as possible and release pedal slowly. The plastic snap fitting in the valve should then retain the piston in the correct position.
- Ignition on.
- Connect the single cable between control module connector terminal 1S and terminal 7T.
- Connect the other cable with the double blade terminal to control module connector terminal 3S, connect one end of the cable to control module connector terminal 9S. Connect the other end of the cable to control module connector terminal 7S.
The vacuum pump should start and the vacuum servo should pull the throttle mechanism to wide open throttle (WOT).

- Stop the vacuum pump when the vacuum servo has fully contracted by disconnecting the cable connected to the control module connector terminal 7S.
- Depress brake pedal.

Does the brake valve let air into the system so that the vacuum servo releases?

Yes - FAULT FOUND

No - Replacing component

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Checking component
- 1. Manual transmission: Checking the clutch valve.
- 2. Automatic transmission: Checking vacuum system completed.

Select one of the alternatives above.

1 - Checking the clutch valve

2 - No Fault Found

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Replacing component

- Ignition off.
- Try a new brake valve according to Replacing brake and clutch valves Service and Repair.

Continue - Verification, vacuum servo

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Checking the clutch valve

- Ignition off.
- Control module disconnected.
- Vacuum pump connected.
- Ignition on.
- Connect the single cable between control module connector terminal 1S and terminal 7T.
- Connect the other cable with the double blade terminal to control module connector terminal 3S, connect one end of the cable to control module connector terminal 9S. Connect the other end of the cable to control module connector terminal 7S.
The vacuum pump should start and the vacuum servo should pull the throttle mechanism to wide open throttle (WOT).

- Stop the vacuum pump when the vacuum servo has fully contracted by disconnecting the cable connected to the control module connector terminal 7S.
- Depress clutch pedal.

Does the clutch valve let air into the system so that the vacuum servo releases?

Yes - No Fault Found

No - Clutch valve adjustment

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Clutch valve adjustment

- Ignition off.
- Disconnect cables.
- Disconnect hose connectors so the vacuum servo releases.
- Press pedal so that it is not in contact with the valve.
- Pull piston out as far as possible and release pedal slowly. The plastic snap fitting in the valve should then retain the piston in the correct position.
- Control module disconnected.
- Vacuum pump connected.
- Ignition on.
- Connect the single cable between control module connector terminal 1S and terminal 7T.
- Connect the other cable with the double blade terminal to control module connector terminal 3S, connect one end of the cable to control module connector terminal 9S. Connect the other end of the cable to control module connector terminal 7S.
The vacuum pump should start and the vacuum servo should pull the throttle mechanism to wide open throttle (WOT).

- Stop the vacuum pump when the vacuum servo has fully contracted by disconnecting the cable connected to the control module connector terminal 7S.
- Depress clutch pedal.

Does the clutch valve let air into the system so that the vacuum servo releases?

Yes - FAULT FOUND

No - Replacing component

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Replacing component

- Ignition off.
- Try a new clutch valve according to Replacing brake and clutch valves Service and Repair.

Continue - Verification, vacuum servo

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Verification, regulator

Verification

Hint: After carrying out the repair, check that the fault has been remedied as follows:

The regulator should click.

OK - VERIFIED

Not OK - VERIFICATION FAILED

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VERIFIED - FAULT FOUND

VERIFICATION FAILED - Fault-tracing information

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Verification, vacuum pump

Verification

Hint: After carrying out the repair, check that the fault has been remedied as follows:

- Ignition off.
- Disconnect control module.
- Vacuum pump connected.
- Ignition on.
Connect the single cable between control module connector terminal 1S and terminal 7T.
Connect the other cable with the double blade terminal to control module connector terminal 3S.
Connect both ends of the cable to terminal 9S and terminal 7S and the vacuum pump will start and the vacuum servo contract. Remove the cable from terminal 7S when the vacuum servo is fully contracted.
Check that the vacuum servo has not released the throttle control at all after 30 seconds.

Did the vacuum pump start?

Yes - VERIFIED

No - VERIFICATION FAILED

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VERIFIED - FAULT FOUND

VERIFICATION FAILED - Fault-tracing information

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Verification, vacuum servo

Verification

Hint: After carrying out the repair, check that the fault has been remedied as follows:

- The vacuum pump should start and pull the vacuum servo fully open.
- Stop the vacuum pump when the vacuum servo has fully contracted by disconnecting the cable connected to the control module connector terminal 7S.
- Depress brake/clutch pedal.

The vacuum pump should now release.

OK - VERIFIED

Not OK - VERIFICATION FAILED

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VERIFIED - FAULT FOUND

VERIFICATION FAILED - Fault-tracing information

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Fault-tracing information

Information

Fault-tracing information
The fault should have been detected and remedied. As this is not the case fault-tracing has failed.
Exit fault-tracing for this diagnostic trouble code (DTC) or make another attempt.

Do you want to exit fault-tracing?

Yes - Exit fault-tracing

No - Attempt New Test

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Attempt New Test - Checking ground lead and power supply

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Connection of Volvo Scan Tool (ST)

Connection of Volvo ST

- Ignition off.
- Insert blue memory cassette into Volvo ST.
- Connect adapter 951 1457-5 to cable 951 1458-3.
- Connect VIDA communication lead between the adapter and the VIDA PC.

Is the data link connector (DLC) located in passenger compartment?

Yes - Connection to DLC

No - Connection to DLC

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Connection to DLC
- Connect Volvo ST cable (p/n 951 1458-3) to the adapter (p/n 951 1459-1) for use in the engine compartment.
- Connect the adapter to DLC A or B, see DLC DLC.
- Connect the adapter supply lead to battery.
- Switch on Volvo ST.

Press Continue.

Continue - DONE

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Connection to DLC
- Connect Volvo ST cable (p/n 951 1458-3) to the DLC in passenger compartment.
- Switch on Volvo ST.

Press Continue.

Continue - DONE

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DONE - Checking vacuum supply pipe

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No Fault Found - No Fault Found

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