| Fault code No. | 42 | |
| Symptom | A. Normal signals are not received from the speed sensor. | |
| B. Open or short circuit of gear position sensor lead | ||
| A | Fail-safe action | Engine startup: Possible |
| Riding: Possible | ||
| Diagnostic monitoring code No. | D:07 (Speed sensor) | |
| Meter display | Vehicle speed pulses: 0-999 | |
| Checking method | Make sure that the indication value increases when the rotation speed of the rear wheel increases. This value is cumulative and is not reset each time the wheel is prevented from rotating. | |
| B | Fail-safe action | Engine startup: Possible |
| Riding: Possible | ||
| Diagnostic monitoring code No. | D:21 (Gear position sensor) | |
| Meter display | Gear position switch ON (neutral) OFF (in gear) | |
| Checking method | Shift the transmission. | |
| Checkpoints | Inspection method |
| Locate the malfunction. | Check in the diagnostic mode (Code No. 07). Rotate the rear wheel and make sure that the indication value increases. Malfunction → Go to the "Speed sensor system malfunction" section below. Check in the diagnostic mode (Code No. 21). When the gear is in neutral position: ON indication. When the gear is not in neutral position: OFF indication. Malfunction → Go to the "Gear position sensor system malfunction section below. |
A. Speed sensor system malfunction
| Item/components and probable cause | Check or maintenance job | Sensor inspection procedure | |
| 1 | Connection of speed sensor (meter) coupler. Check the connection of the coupler is secure. Remove the coupler, and check each pin (for bending, wear, or locking). | Poor connection → Connect it securely, or repair/replace the wire harness. | Start the engine, and check the connection of the coupler is secure. Ride on the vehicle at a low speed (approx. 20-30 km/h). Then, check the fault code indication. No fault code indicated. → Recovered. Fault code indicated. → Check the next step. |
| 2 | Connection of main harness ECU coupler. Check the connection of the coupler is secure. Remove the coupler, and check each pin (for bending, wear, or locking). | Poor connection → Connect it securely, or repair/replace the wire harness. | Start the engine, and check the connection of the coupler is secure. Ride on the vehicle at a low speed (approx. 20-30 km/h). Then, check the fault code indication. No fault code indicated. → Recovered. Fault code indicated. → Check the next step. |
| 3 | Continuity of wire harness | Open or short circuit → Replace the wire harness. Black/Blue-Black/Blue Blue-Blue White/Yellow-White/Yellow | Start the engine, and check the connection of the coupler is secure. Ride on the vehicle at a low speed (approx. 20-30 km/h). Then, check the fault code indication. No fault code indicated. → Recovered. Fault code indicated. → Check the next step. |
| 4 | Speed sensor malfunction Refer to "Checking the speed sensor". | Replace the speed sensor. | Start the engine, and check the connection of the coupler is secure. Ride on the vehicle at a low speed (approx. 20-30 km/h). Then, check the fault code indication. No fault code indicated. → Recovered. Fault code indicated. → Check the next step. |
| 5 | ECU malfunction | Replace the ECU. |
B. Gear position sensor system malfunction
| Item/components and probable cause | Check or maintenance job | Sensor inspection procedure | |
| 1 | Connection of gear position sensor coupler. Check the connection of the coupler is secure. Remove the coupler, and check each pin (for bending, wear, or locking). | Poor connection → Reconnect or repair the coupler. | Start the engine, and check the secure connection of the coupler. Ride the vehicle at a low speed (approx. 20-30 km/h). Then, check the fault code indication. No fault code indicated. → Recovered. Fault code indicated. → Check the next step. |
| 2 | Connection of wire harness ECU coupler. Check the connection of the coupler is secure. Remove the coupler, and check each pin (for bending, wear, or locking). | Poor connection → Reconnect or repair the coupler. | Start the engine, and check the secure connection of the coupler. Ride the vehicle at a low speed (approx. 20-30 km/h). Then, check the fault code indication. No fault code indicated. → Recovered. Fault code indicated. → Check the next step. |
| 3 | Continuity of leads between gear position sensor and relay unit coupler | Open short circuit → Replace the wire harness. Sky blue-Sky blue | Start the engine, and check the secure connection of the coupler. Ride the vehicle at a low speed (approx. 20-30 km/h). Then, check the fault code indication. No fault code indicated. → Recovered. Fault code indicated. → Check the next step. |
| 4 | Gear position sensor malfunction. Refer to "Checking the gear position sensor". | Replace the gear position sensor. | Start the engine, and check the secure connection of the coupler. Ride the vehicle at a low speed (approx. 20-30 km/h). Then, check the fault code indication. No fault code indicated. → Recovered. Fault code indicated. → Check the next step. |
| 5 | Shift drum (that detects the neutral position) malfunction | Check the gear shift drum (that detects the neutral position). Refer to "Checking the shift drum assembly". Malfunction → Replace the shift drum. | Start the engine, and check the secure connection of the coupler. Ride the vehicle at a low speed (approx. 20-30 km/h). Then, check the fault code indication. No fault code indicated. → Recovered. Fault code indicated. → Check the next step. |
| 6 | ECU malfunction | Replace the ECU. |