Troubleshooting Procedure For Speed Sensors{4150, 4803, 5058} Caterpillar

Multi Terrain Loader:

277C (S/N: JWF1-UP)

287C (S/N: MAS1-UP)

297C (S/N: GCP1-UP)

Skid Steer Loader:

246C (S/N: JAY1-UP)

256C (S/N: DWS1-UP)

262C (S/N: MST1-UP)

272C (S/N: RED1-UP)

Introduction

The problem that is identified below does not have a known permanent solution. Until a permanent solution is known, use the solution that is identified below.

Problem

The right and left side 262-3764 Speed Sensor Groups can fail on C-Series Skid Steer Loaders and C-Series Multi terrain Loader. If the speed sensor that is located on the left side fails, the sensor will generate a 2685 or 2686 fault code. If the speed sensor that is located on the right side fails, the sensor will generate a 2687 or 2688 fault code. If a speed sensor fails, the left or the right drive motor may become inoperable. Also, if a speed sensor fails, the machine may steer left or right. Both symptoms should result in the flashing of the warning light. The following may cause fault codes:

• Connections

• Broken Wire(s)

• Metal on Speed Sensor

• Faulty Sensor

• Faulty Drive Motor

Refer to Systems Operation, Troubleshooting, Testing and Adjusting, KENR5119, "Machine Electronic Control System", for specific information on the fault codes.

Solution

1. Use Caterpillar Electronic Technician (CAT ET) in order to check for active fault codes and logged fault codes 2685, 2686, 2687, or 2688. If fault codes are found or the onboard warning light is flashing, proceed to Step 2. Otherwise proceed to Step 7.

2. Check for any broken wires or a harness that is damaged. Refer to Illustration 1. If no problems are found, proceed to Step 3.

   Note: If broken wires or a damaged harness are found, take photographs and attach the photographs to the Service Information Management System (SIMSi). Also, include a comment in the "claim story". Include a photograph that shows the routing of the wire harness. In the photograph, show the location of the tie strap for the speed sensor. This tie strap will be attached to a hydraulic line.

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Illustration 1	g01626193

3. On Multi Terrain Loaders and Compact Track Loaders, ensure that the harness for the speed sensor is properly secured to the upper hose coupling for the drive motor. Use a tie strap in order to secure the harness. Refer to Illustration 2. Ensure that the four-pin connector is routed underneath the driveline. Ensure that the four-pin connector is not routed on the side of the driveline. Proceed to Step 4.

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Illustration 2	g01626539
Routing of Harness for Speed Sensor

4. Inspect the connector on the harness for pins that are not properly seated. Drive the machine in order to clear the stored fault codes. The codes for the speed sensor will remain active until a valid signal is observed by the ECM. If a problem still occurs, proceed to Step 5.

5. Ensure that the connector for the speed sensor is fully seated. Drive the machine in order to clear any fault codes that were stored. The codes for the speed sensor will remain active until a valid signal is seen. If a problem still occurs, proceed to Step 6.

6. Clean up the speed sensor in order to remove any debris. Reinstall the speed sensor and drive the machine in order to clear any stored fault codes. The codes for the speed sensor will remain active until a valid signal is observed by the ECM. Use CAT ET in order to check for active fault codes.

   Note: If debris is found on the sensor, take photographs of the sensor. Attach the pictures to the Service Information Management System (SIMSi). Also include a comment in the "claims story".

7. Proceed to the applicable section of Systems Operation, Troubleshooting, Testing and Adjusting, KENR5119, "Machine Electronic Control System" based on which fault code you are seeing. Use the manual in order to troubleshoot the code.

8. Return the speed sensors that have failed to Caterpillar.