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Home >> Volvo >> 1998 >> V70R AWD L5-2.3L Turbo VIN 52 B5234T6 >> Repair and Diagnosis >> A L L Diagnostic Trouble Codes ( DTC ) >> Testing and Inspection >> Manufacturer Code Charts >> AT / DTC Codes (Transmission Control Module) >> AT-143 Kickdown Switch >> Signal Too Low

Signal Too Low






SPECIAL TOOLS
Test box tool No. 981 3190, or equivalent
Volvo scan tool No. 998 8686, or equivalent

WEAK SIGNAL
1. Status message
- To get the correct status message carry out the following before reading the Diagnostic Trouble Code (DTC):
Ignition ON.
Brake pedal up.
Wait approx. 10 seconds.
Push down the Accelerator Pedal (AP) completely, keep it fully depressed in kickdown mode.
Wait approx. 10 seconds.
- Read out the diagnostic trouble code (DTC).
- Does the status indicate PERMANENT FAULT?
YES: Proceed to step 2
NO: Proceed to step 18





2. Checking kickdown switch function
Preparation:
Ignition ON.
Select scrolling values.
Read off kickdown switch position.
- The reading should only be ON if the accelerator pedal is depressed to kickdown position.
- In other accelerator pedal positions the reading should be OFF.
- Is the correct reading displayed?
YES: Proceed to step 8
NO: Proceed to step 3





3. Checking the kickdown switch
- When the accelerator pedal is depressed fully a circuit is made when the sheath on the throttle cable is pressed in to the kickdown switch.
- Releasing the accelerator pedal allows the cable sheath to spring back and the switch breaks the circuit.

NOTE: The kickdown switch is operated only when the AP is fully depressed.

- Check that the cable sheath is pressed in and springs back when the accelerator pedal is operated.
- Are kickdown switch and cable operation OK?

YES: Proceed to step 5
NO: Proceed to step 4
4. Fault-tracing information
- Correct faults as required.
- Then continue with step 16





5. Checking kickdown switch resistance
- Preparation:
Ignition OFF
Disconnect the kickdown switch.
- Connect an ohmmeter between kickdown switch terminals 1 and 2.
- Fully depress the accelerator pedal.
- The ohmmeter should read approx. 0 Ohms with the accelerator pedal fully depressed and infinite resistance in all other positions.
- Is the correct reading displayed?
YES: Proceed to step 6
NO: Proceed to step 7





6. Checking for short-circuit
- Check cable between kickdown switch terminal 2 and control module #B30 for a short-circuit to ground according to step 3 of checking for permanent faults. Checking For Permanent Faults
- Then continue with step 16





7. Replacing component
- Preparation:
Ignition OFF
- Try a new kickdown switch, refer to Replacement. Service and Repair
- Then continue with step 16





8. Checking voltage drop over the Engine Control Module (ECM) signal ground.
- Preparation:
Ignition OFF
Connect a test box to the ECM (Fenix 5.2, LH 3.2, Motronic 4.3 or Motronic 4.4) as appropriate, refer to Powertrain Management.
Control module connected.
Ignition ON
Turn on as many power consuming items as possible.
- Connect a voltmeter between ground points 31/33 and the test box:
Fenix 5.2: #42 (#A42) signal ground
LH 3.2: #20 (#A20) signal ground
Motronic 4.3: #42 (#A42) signal ground
Motronic 4.4: #42 (#A42) signal ground
- Note the voltmeter reading.
- Then continue with step 9





9. Connecting the test box
- Preparation:
Ignition OFF
Disconnect the test box from the ECM.
- Connect a test box to the automatic Transmission Control Module (TCM) and check ground terminals. Connecting the Test Box
- Then continue with step 10





10. Checking voltage drop over the transmission control module signal ground
- Preparation:
Ignition OFF
Connect the control modules
Ignition ON
Turn on as many power consuming items as possible.
- Connect a voltmeter between ground point 31/33 and #20 (#A20) on the test box.
- Make a note of the reading.
- Add the previous reading obtained to the new reading.
- When added together the sum of the two readings should not be more than 0.1 volt
- If reading is OK:
Proceed to step 12
- If reading is incorrect:
Proceed to step 11





11. Checking for contact resistance and oxidation.
- Preparation:
Ignition OFF
- Check ground terminal 31/33 and TCM connectors for contact resistance and oxidation according to step 5 of checking for permanent faults. Checking For Permanent Faults
- Then continue with step 16





12. Adaptation of the throttle position sensor signal

NOTE:
- If the control module has been replaced the throttle position (TP) signal must be adapted to match the new module.
- Failure to adapt the signal can result in DTC AT-143 being stored.

- Carry out adaptation to wide open throttle as follows:
Block all four wheels.
Start engine.

CAUTION: Apply parking brake and press down hard on the brake pedal with left foot throughout the procedure.

Gear selector to position D
Fully depress the accelerator pedal so the kickdown switch closes.
Keep accelerator pedal fully depressed for 5 seconds .
Release the accelerator pedal and move gear selector to position P.
- Wide Open Throttle (WOT) is now adapted.
- Then continue with step 13





13. hecking Throttle Position (TP) sensor signal
- Preparation:
Ignition OFF
Select scrolling values.
Read off throttle position sensor and kickdown switch positions.
- Depress the accelerator pedal to just before kick down position.
- Check that the throttle position sensor position reads wide open throttle.

NOTE: The kickdown switch should not be moved during the test, it should read OFF.

- Is the throttle position sensor position more than 95% wide open throttle?
YES: Proceed to step 14
NO: Proceed to step 15
14. Fault-tracing information
- The cause of the DTC was the incorrect adaptation of the throttle position sensor signal.
- Then continue with step 16
15. Fault-tracing information
- Fault-trace throttle position sensor signal according to diagnostic trouble code (DTC) AT-223. Signal Too Low
- Then continue with step 16






16. Verification

NOTE: After repairs have been completed they must be verified as follows to ensure that the fault has been eliminated:

- Preparation:
Ignition OFF
Reconnect the connectors, reinstall components etc.
Ignition ON
Brake pedal up.
Wait approx. 10 seconds.
Push down the accelerator pedal completely, keep it fully depressed in kickdown mode.
Wait approx. 10 seconds.
- Read off the diagnostic trouble code (DTC) status.
- Does the status display INTERMITTENT FAULT?
YES: Fault corrected
NO: Proceed to step 17
17. Fault-tracing information
- The verification result shows that the fault persists.
- Do you want to exit fault-tracing?
YES: Fault not corrected
NO: Proceed to step 1





18. Intermittent fault
- Check that the kickdown switch and cable sheath are operating correctly and are not sticking or stiff.
- Check the cable between kickdown switch terminal 2 and control module #B30 for an intermittent short circuit to ground according to step 3 of checking for intermittent faults. Checking For Intermittent Faults
- Check throttle position sensor signal according to step 24 of testing for fault code AT-223 for an intermittent fault. Signal Too Low
- Then continue with step 19
19. Fault-tracing information
- For intermittent faults fault-tracing is not followed by a verification because the fault is not present at this moment.
- Do you want to repeat fault-tracing?
YES: Proceed to step 1
NO: Operation done
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