Operation CHARM: Car repair manuals for everyone.

Signal Too High. Permanent Fault






Signal too high. Permanent fault

EFI-444 Accelerometer, signal

Checking power cable








- Ignition off.
- Disconnect accelerometer.
- Ignition on.
Connect a voltmeter between accelerometer connector terminal 1 and ground.









The voltmeter should read 5 V.

OK - Checking ground lead

Low - Checking power cable resistance to ground

High - Checking for a short-circuit

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Checking for a short-circuit
The accelerometer power cable is connected inside the engine control module (ECM) to the fuel tank pressure sensor, atmospheric pressure sensor and air conditioning (A/C) pressure sensor power cables. If anything happens to any of these cables all four will be affected. Air conditioning (A/C) pressure sensor wiring is pre-routed, even on cars without air conditioning, and should always be checked.
Check cables between:
- Accelerometer terminal 1 and engine control module (ECM) #B1.
- Air conditioning (A/C) pressure sensor terminal 3 and engine control module (ECM) #B29.
- atmospheric pressure sensor terminal 1 and engine control module (ECM) #B29
- tank pressure sensor terminal 1 and engine control module (ECM) #B15 for a short-circuit to supply voltage according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.





Continue - Verification

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Checking ground lead








- Ignition off.
- Accelerometer disconnected.
Connect an ohmmeter between accelerometer connector terminal 2 and ground.









The ohmmeter should read approximately 0 ohms.

OK - Checking the signal cable

Not OK - Checking control module connector

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Checking control module connector












- Ignition off.
- Accelerometer disconnected.
- Check control module connector for contact resistance and oxidation and remedy according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.
- Control module connected.
Connect an ohmmeter between accelerometer connector terminal 2 and ground.









The ohmmeter should read approximately 0 ohms.

OK - Fault-tracing information

Not OK - Checking for an open-circuit

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Checking for an open-circuit








- Check cable between accelerometer terminal 2 and engine control module (ECM) #B28 for an open-circuit according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.

Continue - Verification

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Fault-tracing information
The cause of the diagnostic trouble code (DTC) has been loose connections in the control module connector.

Continue - Verification

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Checking the signal cable








- Ignition on.
- Accelerometer disconnected.
Connect a voltmeter between accelerometer connector terminal 3 and ground.









The voltmeter should read approximately 5 V.

OK - Checking accelerometer

Low - Checking control module connector

High - Checking for a short-circuit

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Checking for a short-circuit








- Check cable between accelerometer terminal 3 and engine control module (ECM) #B32 for a short-circuit to supply voltage according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.





Continue - Verification

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Checking control module connector












- Ignition off.
- Accelerometer disconnected.
- Check control module connector for contact resistance and oxidation and remedy according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.
- Control module connected.
- Ignition on.
Connect a voltmeter between accelerometer connector terminal 3 and ground.









The voltmeter should read approximately 5 V.

OK - Fault-tracing information

Not OK - Checking for an open-circuit

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Fault-tracing information
The cause of the diagnostic trouble code (DTC) has been loose connections in the control module connector.

Continue - FAULT FOUND

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Checking for an open-circuit








- Check cable between accelerometer terminal 3 and engine control module (ECM) #B32 for an open-circuit according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.





Continue - Verification

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Checking accelerometer








- Ignition on.
- Connect the accelerometer.




- Select Volvo Scan Tool (ST) to erase diagnostic trouble code (DTC).

Continue - Checking accelerometer, continued

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Checking accelerometer, continued








- Accelerometer connected.
- Start the engine and idle it.




- Select Volvo Scan Tool (ST) to read off diagnostic trouble code (DTC).

Does the diagnostic trouble code (DTC) recur?

Yes - Replacing component

No - Fault-tracing information

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Fault-tracing information
The cause of the diagnostic trouble code (DTC) has been loose connections in the accelerometer connector.
- Check connector for contact resistance and oxidation and remedy according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.

Continue - Verification

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Replacing component
- Try a new accelerometer.





Continue - Verification

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Checking power cable resistance to ground








- Ignition off.
- Accelerometer disconnected.
- Wait for approximately 150 seconds (cars with immobilizer 245 seconds).
Connect an ohmmeter between accelerometer connector terminal 1 and ground.









The ohmmeter should read 0.2 - 1.5 kohms.

OK - No Fault Found

Low - Car equipment level

High - Checking control module connector

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Car equipment level
The following options are available:
- 1. the car has air conditioning (A/C).
- 2. the car does not have air conditioning (A/C), but does have a leak diagnostic.
- 3. the car has neither air conditioning (A/C) or a leak diagnostic.

Select a suitable alternative.

1 - Checking the air conditioning (A/C) pressure sensor

2 - Checking fuel tank pressure sensor

3 - Checking for a short-circuit

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Checking control module connector












- Ignition off.
- Accelerometer disconnected.
- Check control module connector for contact resistance and oxidation and remedy according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.
- Control module connected.
Connect an ohmmeter between accelerometer connector terminal 1 and ground.









The ohmmeter should read approximately 0.2 - 1.5 kohms.

OK - Fault-tracing information

Not OK - Checking for an open-circuit

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Checking the air conditioning (A/C) pressure sensor








- Ignition off.
- Accelerometer disconnected.
- Disconnect the air conditioning (A/C) pressure sensor.
Connect an ohmmeter between accelerometer connector terminal 1 and ground.









The ohmmeter should read 0.2 - 1.5 kohms.

OK - Replacing component

Not OK - Car equipment level

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Car equipment level

Does the car have leak diagnosis?

Yes - Checking fuel tank pressure sensor

No - Checking for a short-circuit

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Checking fuel tank pressure sensor








- Ignition off.
- Accelerometer disconnected.
- Air conditioning (A/C) pressure sensor disconnected.
- Disconnect tank pressure sensor.
Connect an ohmmeter between accelerometer connector terminal 1 and ground.









The ohmmeter should read 0.2 - 1.5 kohms.

OK - Replacing component

Not OK - Checking atmospheric pressure sensor

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Checking atmospheric pressure sensor








- Ignition off.
- Accelerometer disconnected.
- Air conditioning (A/C) pressure sensor disconnected.
- Fuel tank pressure sensor disconnected.
- Disconnect atmospheric pressure sensor.
Connect an ohmmeter between accelerometer connector terminal 1 and ground.









The ohmmeter should read 0.2 - 1.5 kohms.

OK - Replacing component

Not OK - Checking for a short-circuit

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Replacing component
- Try a new atmospheric pressure sensor.





Continue - Verification

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Checking for a short-circuit
The accelerometer power cable is connected inside the engine control module (ECM) to the fuel tank pressure sensor, atmospheric pressure sensor and air conditioning (A/C) pressure sensor power cables. If anything happens to any of these cables all four will be affected. Air conditioning (A/C) pressure sensor wiring is pre-routed, even on cars without air conditioning, and should always be checked.
Check cables between:
- Accelerometer terminal 1 and engine control module (ECM) #B1.
- Air conditioning (A/C) pressure sensor terminal 3 and engine control module (ECM) #B29.
- atmospheric pressure sensor terminal 1 and engine control module (ECM) #B29
- tank pressure sensor terminal 1 and engine control module (ECM) #B15.
- for a short-circuit to ground according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.





Continue - Verification

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Checking for an open-circuit








- Check cable between accelerometer terminal 1 and engine control module (ECM) #B1 for an open-circuit according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.

Continue - Verification

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Replacing component
- Try a new air conditioning (A/C) pressure sensor.





Continue - Verification

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Replacing component
- Try a new fuel tank pressure sensor.





Continue - Verification

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Verification




Verification

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








- Ignition off.
- Accelerometer and, if necessary, air conditioning (A/C) pressure sensor and fuel tank pressure sensor connected.
- Start the engine and idle it.




- Select Volvo Scan Tool (ST) to read off the value of the from the accelerometer.

The value should be approximately 2.5 V.

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 power cable

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