Operation CHARM: Car repair manuals for everyone.

Signal Too High. Permanent Fault






Signal too high. Permanent fault

EFI-422 Atmospheric pressure sensor, signal

Checking ground lead








- Ignition off.
- Wait for approximately 150 seconds (cars with immobilizer 245 seconds).
- Disconnect atmospheric pressure sensor (lilac connector).
Connect an ohmmeter between atmospheric pressure sensor connector 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.
- Atmospheric pressure sensor 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 atmospheric pressure sensor connector 2 and ground.









The ohmmeter should read approximately 0 ohms.

OK - Checking the signal cable

Not OK - Checking for an open-circuit

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Checking for an open-circuit








- Check cable between atmospheric pressure sensor 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.





Select "Continue" when the fault has been repaired.

Continue - Verification

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Checking the signal cable








- Ignition on.
- Atmospheric pressure sensor disconnected.
Connect an electrician's screwdriver (3 W bulb at least) between atmospheric pressure sensor connector terminal 2 and ground.









The bulb should not light.

OK - Checking signal cable resistance

Not OK - Checking for a short-circuit

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Checking for a short-circuit








- Check the cable between atmospheric pressure sensor terminal 3 and engine control module (ECM) #B22 for a short-circuit to supply voltage according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.

Select "Continue" when the fault has been repaired.

Continue - Verification

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Checking signal cable resistance








- Ignition off.
- Atmospheric pressure sensor disconnected.
Connect an ohmmeter between atmospheric pressure sensor connector 3 and ground.









The ohmmeter should read less than approximately 10 kohms.

OK - Checking power cable

Not OK - Checking for an open-circuit

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Checking for an open-circuit








- Check the cable between atmospheric pressure sensor terminal 3 and engine control module (ECM) #B22 for an open-circuit according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.

Select "Continue" when the fault has been repaired.

Continue - Verification

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Checking power cable








- Ignition on.
- Atmospheric pressure sensor disconnected.
Connect a voltmeter between atmospheric pressure sensor connector terminal 1 and ground.









The voltmeter should read approximately 5 V.

OK - Replacing component

Not OK - Checking cables

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Replacing component
- Try a new atmospheric pressure sensor.





Select "Continue" when the fault has been repaired.

Continue - Verification

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Checking cables








- Ignition off.
- Disconnect air conditioning (A/C) pressure sensor, fuel tank pressure sensor and accelerometer.
- Atmospheric pressure sensor disconnected.
- Ignition on.
Connect a voltmeter between atmospheric pressure sensor connector terminal 1 and ground.









The voltmeter should read approximately 5 V.

OK - Checking fuel tank pressure sensor

Not OK - Checking for a short-circuit

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Checking for a short-circuit
The atmospheric pressure sensor power cable is connected inside the engine control module (ECM) to the air conditioning (A/C) pressure sensor, fuel tank pressure sensor and accelerometer power cables.
If anything happens to any of these cables all four will be affected.
Check cables between:
- Air conditioning (A/C) pressure sensor terminal 3 and engine control module (ECM) #B29.
- tank pressure sensor terminal 1 and engine control module (ECM) #B15.
- Accelerometer terminal 1 and engine control module (ECM) #B1.
- atmospheric pressure sensor terminal 1 and engine control module (ECM) #B29
- for a short-circuit to supply voltage according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.





Select "Continue" when the check has been made.

Continue - Verification

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Checking fuel tank pressure sensor




- Ignition off.
- Connect fuel tank pressure sensor.
- Atmospheric pressure sensor, air conditioning (A/C) pressure sensor and accelerometer disconnected.
- Ignition on.
Connect a voltmeter between atmospheric pressure sensor terminal 1 and ground.









The voltmeter should read approximately 5 V.

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

Not OK - Replacing component

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Replacing component
- Try a new fuel tank pressure sensor.





Select "Continue" when the fault has been repaired.

Continue - Verification

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Checking the air conditioning (A/C) pressure sensor




- Ignition off.
- Connect air conditioning (A/C) pressure sensor.
- Atmospheric pressure sensor and accelerometer disconnected.
- Ignition on.
Connect a voltmeter between atmospheric pressure sensor terminal 1 and ground.









The voltmeter should read approximately 5 V.

OK - Replacing component

Not OK - Replacing component

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Replacing component
- Try a new accelerometer.





Select "Continue" when the fault has been repaired.

Continue - Verification

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





Select "Continue" when the fault has been repaired.

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.
- Reconnect connectors and reinstall components.
- Start the engine and idle it.
- Wait for a minute.




- Select Volvo Scan Tool (ST) to read off diagnostic trouble codes (DTCs).

If EFI-422 is stored it should have intermittent status.

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

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