Info - AISIN Automatic Transmission False DTC Code 11 Set
| Subject: | AISIN Automatic Transmission False DTC Code 11 Set |
| Models: | 1999-2002 Chevrolet and GMC W-Series Medium Duty Tilt Cab Models |
| 1999-2002 Isuzu N-Series Commercial Vehicles |
| with Diesel Engine and AISIN Automatic Transmission (AT) |
When diagnosing the above vehicles using the Tech 2®, technicians may find transmission DTC code 11 (Vehicle Speed Sensor 1 circuit malfunction) stored in Transmission Control Module (TCM) memory. Under certain vehicle operating conditions unrelated to speed sensor circuit failure, DTC 11 might be set without illuminating the "Check Trans" light. Specifically, if the vehicle is driven steadily at very low speeds (below 30 feet per minute) for an extended period of time, the code will set.
First, clear the code from TCM memory and road test the vehicle at normal road speeds. In the "Data Display" section of the Tech 2®, observe "vehicle speed sensor 1 (VSS-1)" miles-per-hour.
| • | If the indicated road speed increases with vehicle speed and DTC 11 is not reset, then this condition is only a transmission control logic error and no system malfunction exists. Do not replace the sensor or the TCM. |
| • | If DTC 11 resets, then follow the DTC 11 troubleshooting procedure below to determine the cause of VSS-1 circuit malfunction. |
DTC 11 Troubleshooting Procedure
- Block the front wheels. Raise the rear axle and place securely on jackstands.
- Using a digital volt-ohm meter set on AC voltage, backprobe the TCM connector B229-16 (-) and B229-3 (+). The TCM is mounted under the instrument panel to the left of the steering column.
- Start the engine. The meter should read 0 V AC with the vehicle stopped (rear tires stopped).
- Place the transmission selector in "D" position. Voltage should increase as rear wheel speed increases. Accelerate the engine until speedometer indicates approximately 24 km/h (15 mph). The voltmeter should read at least 1 V AC. If voltage is OK, vehicle is normal. If voltage is not OK, proceed to step 5 below.
- With the engine off, disconnect the B229 connector at the TCM. Measure VSS-1 circuit resistance using the digital volt-ohm meter set on ohms. Backprobe the TCM connector at terminals B229-16 (-) and B229-3 (+). The resistance displayed should read between 500 to 1000 ohms.
- If the resistance is greater than 1000 ohms or infinite ∞, test the resistance of the sensor at the J-73 two pin VSS-1 connector. If resistance is greater than 1000 ohms or infinite ∞, then replace the sensor. If the resistance is normal, then find the open or short in the harness between the TCM and VSS-1.
Warranty Information
For vehicles repaired under warranty, use:
Labor Operation | Description | Labor Time |
|---|---|---|
K6310 | Inspect VSS-1 Circuit, No Problem Found | 0.3 hr |
Add | To Repair Harness or Replace Sensor | 0.3 hr |
