ABS/TCS - Warning Lamp ON/DTC's Set
No: 70/01/06/NASFGN 206-06
Replaces: 70/07/04/NAS
70/02/05/NAS
Issue: 1
Date: March 17, 2006
Shuttle Valve Switch Related ABS/TC/HDC Warning Lamp Illumination Troubleshooting
AFFECTED VEHICLE RANGE:
Discovery Series II (LT) All
SITUATION:
WARNING LAMP ILLUMINATION
A customer may report that the anti-lock braking system (ABS), traction control (IC) and hill descent control (HDC) warning lamps are illuminated.
This bulletin has been issued to replace 70/07/04/NAS and 70/02/05/NAS. It includes additional repair options and fault diagnosis information relating to the following Diagnostic Trouble Codes (DTC) if logged when the ABS ECU is interrogated by T4/RDS:
^ 1.6 - Shuttle valve switch (SVS) long term supervision failure
^ 11.1 - One sticking SVS
^ 11.4 - SVS electrical supervision failure
RESOLUTION:
FOLLOW TROUBLESHOOTING PROCEDURES
NOTE:
This bulletin has been issued to replace previous bulletins. It changes the causal part number, includes an updated diagnostic procedure and introduces a shuttle valve switch service kit.
Should a customer express concern regarding illuminated ABS, TC and HDC warning lights, refer to the Diagnostic and Repair Procedure detailed in this bulletin. The cause of an SVS failure warning does not necessarily come from the Modulator. The troubleshooting procedure in this bulletin should be used to diagnose the problem further and ensure that the correct action is taken.
A service optimization procedure has been introduced for ABS Modulators that enables new shuttle valve switches to be installed to the modulator. The Diagnostic Procedure will determine if installing a new SVS is the appropriate repair. ABS Modulators should not be replaced unnecessarily.
NOTE:
The ABS modulator should not be replaced if the root cause of the problem is a wiring fault.
Wiring faults external to the ABS modulator may also cause SVS fault codes. The diagnostic procedure will determine if an external wiring problem is the root cause of the symptoms. Wiring faults may be intermittent due to hidden breaks and poor connections. Always try to provoke intermittent faults by flexing wires while checking. Faulty wires should be repaired.
PARTS
TOOL
DDW WARRANTY CLAIMS:
NOTE:
Repair procedures are under constant review, and therefore times are subject to change; those quoted here must be taken as guidance only. Always refer to DDW to obtain the latest repair time.
DDW requires the use of causal part numbers. Labor only claims must show the causal part number with a quantity of zero.
DIAGNOSTIC AND REPAIR PROCEDURE
INVESTIGATE FAULT CODES AND REPAIR WIRING AS INDICATED
NOTE:
Wiring faults may be intermittent due to hidden breaks and poor connections.
^ When checking for wiring faults, always try to provoke intermittent faults by flexing wires while checking.
^ For connector views not detailed in this bulletin, refer to the appropriate Electrical Library.
^ For all electrical repairs refer to the guidelines shown in the Discovery 1999MY Electrical Library LRL0529 (Introduction, Harness Repairs).
NOTE:
If a fault is confirmed and a rectification carried out, the step/rectification must be retested and then the remainder of the diagnostic procedure should be completed.
1. Position the ignition to the OFF position and perform the following:
^ Inspect the ground stud connection C0561-1 for damage and corrosion. (Figure 1)
^ If the ground stud is damaged or corroded clean the eyelet and stud and tighten the nut to 10 Nm (7.5 lbf-ft).
^ Check for continuity between the ground stud C0561-1 and the black wire on the ABS modulator body connector C0500. (Figure 2)
^ If there is no continuity, or intermittent continuity when the wire is flexed, repair the damaged wire and ensure the splice is correctly crimped and sealed.
CAUTION:
Connector pins must only be renewed one at a time to ensure the pins are returned to the correct position.
2. Disconnect and check the 13-pin connector at the ABS modulator (C0501). (Figure 3)
3. Disconnect the 15-pin connector C0506 at the Self Leveling and Anti-lock Braking (SLABS) ECU. (Figure 4)
4. Inspect both connectors for moisture ingress or corrosion and correct as follows:
^ If moisture or corrosion is present, dry and clean the connectors.
^ Repair corroded connectors as necessary.
5. With connectors C0501 and C0506 disconnected perform the following:
^ Check for continuity between pin 6 of the 15-pin SLABS ECU connector (C0506) and pin 9 of the 13-pin ABS modulator connector (C0501) yellow/green wire.
^ If there is no continuity (or intermittent continuity when the wire is flexed), repair as necessary and ensure the wire is correctly crimped and soldered.
^ Check for continuity between pin 3 of the 15-pin SLABS ECU connector (C0506) and pin 8 of the 13-pin ABS modulator connector (C0501) black/slate wire.
^ If there is no continuity (or intermittent continuity when the wire is flexed), repair as necessary and ensure the wire is correctly crimped and soldered.
6. Disconnect the 18-pin SLABS ECU connector (C0504).
7. Check for continuity between pin-12 of C0504 and the ground connection located under the left-hand side of the fascia (C0362 - black wire). (Figure 5)
8. If there is no continuity (or intermittent continuity when the wire is flexed), repair as necessary and ensure the wire is correctly crimped and soldered.
9. Connect the connectors to the SLABS ECU and ABS Modulator.
10. If repairs were completed, clear all logged codes using T4 and perform the following:
^ Road test the vehicle.
^ If no DTCs return, no further action is required.
DIAGNOSE ABS MODULATOR AND REPAIR AS INDICATED
CAUTION:
The safety precautions detailed in the Workshop Manual relating to braking systems must be adhered to.
NOTE:
Discovery Series II 1999MY onwards Workshop Manual Section 70, Brakes - Modulator unit - ABS (70.65.49)
1. If no wiring concerns were found during the continuity checks, refer to GTR section 70.65.49 and remove the ABS modulator from the vehicle.
2. Place the ABS modulator on clean work surface and check for continuity between pin 8 of the 13-pin modulator connector (C0501-8) and the single adjacent modulator ground pin (C0500-1). (Figure 6)
3. If there is no continuity in the test above, obtain a new ABS modulator and go to the "INSTALLATION AND FINAL VERIFICATION" section.
CAUTION:
This procedure should be carried out in a clean working environment.
NOTE:
There may be a slight covering of brake fluid behind the black plastic cover when removed. This is normal and is not a cause for concern. The shuttle valve switches are located behind the black plastic cover opposite the hydraulic ports.
4. If there is continuity in the test above in step 12, remove the plastic cover from the modulator as follows: (Figure 7)
^ Remove the three cap-head bolts holding the cover in place.
^ Carefully pull the cover away from the modulator in order to get access to the SVS connector behind the cover.
^ If there is evidence of excessive brake fluid leakage (fluid dripping from the cover when the cover is removed), obtain a new ABS modulator and go to the "INSTALLATION AND FINAL VERIFICATION" section.
^ If there is no brake fluid present, pull the connector apart and remove the shuttle valve switches and black plastic cover as an assembly.
^ Clean any excess residual thread lock from the SVS mounting bolt holes.
CAUTION:
The black plastic cover must be secure and may not be cracked when installed.
5. Install the new shuttle valve switch pack from the service kit as follows:
^ Connect the electrical connector.
6 Carefully push the cover into the modulator.
^ Install the three cap-head screws from the service kit and tighten to 4 Nm (3 lbf-ft).
6. Measure the resistance between pin 9 on the 13-pin modulator connector (C0501-9) and the single adjacent modulator ground pin (C0500-1).
7. If the resistance value observed is outside the 3020 Ohms +/- 30 Ohms limit, obtain a new ABS modulator and go to the "INSTALLATION AND FINAL VERIFICATION" section below.
INSTALLATION AND FINAL VERIFICATION
1. Refer to GTR Section 70.65.49 and install the ABS modulator from the vehicle or the new unit if testing indicated replacement was required.
2. Clear any logged DTCs using T4 and disconnect the diagnostic equipment from the vehicle.
3. Road test the vehicle including a number of drive cycles to verify that none of the SVS DTCs return and include the following elements in the road test:
^ Light acceleration.
^ Light braking.
^ Ignition resets while stationary.
4. Connect T4 and verify that no SVS DTCs have returned.
5. Verify that the Internal ECU Data Shuttle Valve Switch Failure Count (ODH LSB) is zero.
6. If the failure count is not zero or if any SVS DTCs have returned, replace the ABS modulator with a new unit.
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