SAAB WIS ONLINE

PRE-RELEASE

DTC 27 OPEN OR SHORT CIRCUIT IN REAR LEFT ABS WHEEL SPEED SENSOR CIRCUIT

DTC 27 OPEN OR SHORT CIRCUIT IN REAR LEFT ABS WHEEL SPEED SENSOR CIRCUIT

DIAGNOSIS:


Faulty ABS wheel speed sensor (Broken wire, input voltage too high)

Faulty harness connector


TROUBLE SYMPTOM:

ABS does not operate.

WIRING DIAGRAM:


CHECK OUTPUT OF ABS WHEEL SPEED SENSOR USING Vehicle Diagnostic Interface.

Select “Current data display & Save” on the Vehicle Diagnostic Interface.

Read the ABS wheel speed sensor output corresponding to faulty system in the Vehicle Diagnostic Interface data display mode.

Does the speed indicated on display change in response to speedometer reading during acceleration/deceleration when the steering wheel is in straight-ahead position?

Yes


No


CHECK INSTALLATION OF ABS WHEEL SPEED SENSOR.

Are the ABS wheel speed sensor installation bolts tightened 33 Nm (3.3 kgf-m, 24 ft-lb)?

Yes


No

Tighten the ABS wheel speed sensor installation bolts securely.


CHECK ABS WHEEL SPEED SENSOR GAP.

Measure the tone wheel to ABS wheel speed sensor piece gap over entire perimeter of the wheel.

Is the gap as following value? Front wheel: 0.3 — 0.8 mm (0.012 — 0.031 in) Rear wheel 0.7 — 1.2 mm (0.028 — 0.047 in)

Yes


No

Adjust the gap.

Note

Adjust the gap using spacers (Part No. 32009555). If the spacers cannot correct gap, replace worn sensor or worn tone wheel.



CHECK TONE WHEEL RUNOUT.

Measure the tone wheel runout.

Is the runout less than 0.05 mm (0.0020 in)?

Yes


No

Replace the tone wheel. Front: Rear:


CHECK POOR CONTACT IN CONNECTORS.

Turn the ignition switch to OFF.

Is there poor contact in connectors between ABSCM&H/U and ABS wheel speed sensor?

Yes

Repair the connector.


No


CHECK ABSCM&H/U.

Connect all connectors.

Erase the memory.

Perform the inspection mode.

Read out the DTC.

Is the same DTC as in the current diagnosis still being output?

Yes

Replace the ABSCM&H/U.


No


CHECK ANY OTHER DTC APPEARANCE.

Are other DTCs being output?

Yes

Proceed with the diagnosis corresponding to DTC.


No

A temporary poor contact.

Note

Check the harness and connectors between ABSCM&H/U and ABS wheel speed sensor.



CHECK ABS WHEEL SPEED SENSOR.

Turn the ignition switch to OFF.

Disconnect the connector from ABS wheel speed sensor.

Measure the resistance of ABS wheel speed sensor connector terminals while shaking the harness lightly.

Terminals

Front RH No. 1 — No. 2:

Front LH No. 1 — No. 2:

Rear RH No. 1 — No. 2:

Rear LH No. 1 — No. 2:

Is the resistance as following value? Front: 1 — 1.5 kΩ Rear: 1.025 — 1.265 kΩ

Yes


No

Replace the ABS wheel speed sensor. Front: Rear:


CHECK BATTERY SHORT OF ABS WHEEL SPEED SENSOR.

Disconnect the connector from ABSCM& H/U.

Measure the voltage between ABS wheel speed sensor and chassis ground.

Terminals

Front RH No. 1 (+) — Chassis ground (−):

Front LH No. 1 (+) — Chassis ground (−):

Rear RH No. 1 (+) — Chassis ground (−):

Rear LH No. 1 (+) — Chassis ground (−):

Is the voltage less than 1 V?

Yes


No

Replace the ABS wheel speed sensor. Front: Rear:


CHECK BATTERY SHORT OF ABS WHEEL SPEED SENSOR.

Turn the ignition switch to ON.

Measure the voltage between ABS wheel speed sensor and chassis ground.

Terminals

Front RH No. 1 (+) — Chassis ground (−):

Front LH No. 1 (+) — Chassis ground (−):

Rear RH No. 1 (+) — Chassis ground (−):

Rear LH No. 1 (+) — Chassis ground (−):

Is the voltage less than 1 V?

Yes


No

Replace the ABS wheel speed sensor. Front: Rear:


CHECK HARNESS/CONNECTOR BETWEEN ABSCM&H/U AND ABS WHEEL SPEED SENSOR.

Turn the ignition switch to OFF.

Connect the connector to ABS wheel speed sensor.

Measure the resistance between ABSCM&H/U connector terminals.

Connector & terminal

DTC 21

(B301) No. 6 — No. 5:

DTC 23

(B301) No. 1 — No. 16:

DTC 25

(B301) No. 19 — No. 4:

DTC 27

(B301) No. 3 — No. 2:

Is the resistance as following value? Front: 1 — 1.5 kΩ Rear: 1.025 — 1.265 kΩ

Yes


No

Repair the harness/connector between ABSCM&H/U and ABS wheel speed sensor.


CHECK BATTERY SHORT OF HARNESS.

Measure the voltage between ABSCM&H/U connector and chassis ground.

Connector & terminal

DTC 21

(B301) No. 5 (+) — Chassis ground (−):

DTC 23

(B301) No. 16 (+) — Chassis ground (−):

DTC 25

(B301) No. 4 (+) — Chassis ground (−):

DTC 27

(B301) No. 2 (+) — Chassis ground (−):

Is the voltage less than 1 V?

Yes


No

Repair the harness between ABSCM&H/U and ABS wheel speed sensor.


CHECK BATTERY SHORT OF HARNESS.

Turn the ignition switch to ON.

Measure the voltage between ABSCM&H/U connector and chassis ground.

Connector & terminal

DTC 21

(B301) No. 5 (+) — Chassis ground (−):

DTC 23

(B301) No. 16 (+) — Chassis ground (−):

DTC 25

(B301) No. 4 (+) — Chassis ground (−):

DTC 27

(B301) No. 2 (+) — Chassis ground (−):

Is the voltage less than 1 V?

Yes


No

Repair the harness between ABSCM&H/U and ABS wheel speed sensor.


CHECK INSTALLATION OF ABS WHEEL SPEED SENSOR.

Are the ABS wheel speed sensor installation bolts tightened 33 Nm (3.3 kgf-m, 24 ft-lb)?

Yes


No

Tighten the ABS wheel speed sensor installation bolts securely.


CHECK ABS WHEEL SPEED SENSOR GAP.

Measure the tone wheel to ABS wheel speed sensor piece gap over entire perimeter of the wheel.

Is the gap as following value? Front wheel: 0.3 — 0.8 mm (0.012 — 0.031 in) Rear wheel: 0.7 — 1.2 mm (0.028 — 0.047 in)

Yes


No

Adjust the gap.

Note

Adjust the gap using spacers (Part No. 32009555). If the spacers cannot correct gap, replace worn sensor or worn tone wheel.



CHECK TONE WHEEL RUNOUT.

Measure the tone wheel runout.

Is the runout less than 0.05 mm (0.0020 in)?

Yes


No

Replace the tone wheel. Front: Rear:


CHECK GROUND SHORT OF ABS WHEEL SPEED SENSOR.

Turn the ignition switch to ON.

Measure the resistance between ABS wheel speed sensor and chassis ground.

Terminals

Front RH No. 1 — Chassis ground:

Front LH No. 1 — Chassis ground:

Rear RH No. 1 — Chassis ground:

Rear LH No. 1 — Chassis ground:

Is the resistance more than 1 MΩ?

Yes


No

Replace the ABS wheel speed sensor and ABSCM&H/U. Front: Rear: and


CHECK GROUND SHORT OF HARNESS.

Turn the ignition switch to OFF.

Connect the connector to ABS wheel speed sensor.

Measure the resistance between ABSCM&H/U connector terminal and chassis ground.

Connector & terminal

DTC 21

(B301) No. 6 — Chassis ground:

DTC 23

(B301) No. 1 — Chassis ground:

DTC 25

(B301) No. 19 — Chassis ground:

DTC 27

(B301) No. 3 — Chassis ground:

Is the resistance more than 1 MΩ?

Yes


No

Repair the harness between ABSCM&H/U and ABS wheel speed sensor.

And replace the ABSCM&H/U.


CHECK POOR CONTACT IN CONNECTORS.

Is there poor contact in connectors between ABSCM&H/U and ABS wheel speed sensor?

Yes

Repair the connector.


No


CHECK ABSCM&H/U.

Connect all connectors.

Erase the memory.

Perform the inspection mode.

Read out the DTC.

Is the same DTC as in current diagnosis still being output?

Yes

Replace the ABSCM&H/U.


No


CHECK ANY OTHER DTC APPEARANCE.

Are other DTCs being output?

Yes

Proceed with the diagnosis corresponding to DTC.


No

A temporary poor contact.

Note

Check the harness and connectors between ABSCM&H/U and ABS wheel speed sensor.



PRE-RELEASE