| Table 1: | DTC P1740 Torque Control Circuit (Transmission) |
| Table 2: | DTC P1740 Torque Control Circuit (ABS/TC) |
Circuit Description
Part 1 (Transmission):
The ECM pulls the torque management input circuit up to 12 volts and monitors this circuit. The TCM also monitors this circuit. This circuit provides uni-directional communication between the two controllers. The messages are sent every 25 msec. This data is used in order to reduce the engine torque during the transmission shift events in order to improve the shift feel. If the ECM detects a problem on this circuit, this DTC will set.
Part 2 (Traction Control):
The ECM monitors the torque reduction request input circuit. The ABS/TC Module also monitors this circuit. This circuit provides uni-directional communication between the two controllers. This data is used in order to reduce the engine torque during a wheel slipping condition where traction control is needed. If the ECM detects a problem on this circuit, this DTC will set.
Conditions for Running the DTC
Part 1 (Transmission):
Tested continuously
Part 2 (Traction Control):
| • | Engine speed is greater than 600 RPM |
| • | Tested continuously |
Conditions for Setting the DTC
Part 1 (Transmission):
| • | The signal remains low for at least 2 seconds. |
| OR |
| • | The signal is low 3 times for at least 2.5 seconds. |
| • | The above condition met within 10 seconds. |
Part 2 (Traction Control):
| • | The signal is out of range. |
| • | The above condition met for 2.5 seconds. |
Action Taken When the DTC Sets
Part 1:
The ECM will not illuminate the Malfunction Indicator Lamp (MIL).
Part 2:
| • | The ECM will not illuminate the Malfunction Indicator Lamp (MIL). |
| • | The ECM informs the ABS/TC Module that this DTC was set. |
Conditions for Clearing the MIL/DTC
| • | A History DTC clears after forty consecutive warm-up cycles if no failures report by this diagnostic or any other emission related diagnostic. |
| • | The ECM battery voltage is interrupted. |
| • | The scan tool clears the DTC. |
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Did you perform the Powertrain On-Board Diagnostic (OBD) System check? | -- | ||
2 |
Does the DVM indicate the specified voltage? | B+ | ||
3 | Probe the Torque Management Request Circuit in the TCM harness connector with the test light J 34142-B connected to ground. Does the test light illuminate? | -- | ||
4 |
Is continuity indicated? | -- | ||
5 | Check the harness for continuity between the Torque Management Request Circuit and battery ground with the DVM J 39200 . Is continuity indicated? | -- | ||
6 | Turn off the ignition. Reconnect the TCM. Disconnect the ECM. Probe the Torque Management Request Circuit in the TCM harness connector with the test light J 34142-B connected to B+. Does the test light illuminate? | -- | Fault not present. Refer to Diagnostic Aids | |
7 | Repair the circuit shorted to B+. Is the action complete? | -- | -- | |
8 | Repair the open/high resistance circuit. Is the action complete? | -- | -- | |
9 | Repair the circuit shorted to ground. Is the action complete? | -- | -- | |
10 | Replace the TCM. Is the action complete? | -- | -- | |
11 | Check for a poor connection or poor terminal tension at the ECM harness connector. Refer to Electrical Diagnosis in Engine Electrical, and Trouble Shooting Procedures for the proper procedure. Also, refer to Checking Terminal Contact in Engine Control Module Diagnosis . Was a problem found and corrected? | -- | ||
12 |
Important: This vehicle is equipped with a Theft Deterrent System which interfaces with the Engine Control Module (ECM). Program the new ECM with the frequency code of the theft deterrent module that is currently on the vehicle. Replace the ECM. Refer to Engine Control Module Replacement/Programming . Is the action complete? | -- | -- | |
13 |
Is this DTC set? | -- | ||
14 | Were there any additional DTCs noted during the Powertrain OBD System Check that have not been diagnosed? | -- | Go to the applicable DTC table | The System is OK |
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Did you perform the Powertrain On-Board Diagnostic (OBD) System check? | -- | ||
2 |
Does the DVM indicate the specified voltage? | 0V | ||
3 | Probe the Torque Management Request Circuit in the ABS/TC Module harness connector with the test light J 34142-B connected to ground. Does the test light illuminate? | -- | ||
4 |
Is continuity indicated? | -- | ||
5 | Check the harness for continuity between the Torque Management Request Circuit and battery ground with the DVM J 39200 . Is continuity indicated? | -- | ||
6 |
Does the test light illuminate? | -- | Fault not present. Refer to Diagnostic Aids | |
7 | Repair the circuit shorted to B+. Is the action complete? | -- | -- | |
8 | Repair the open/high resistance circuit. Is the action complete? | -- | -- | |
9 | Repair the circuit shorted to ground. Is the action complete? | -- | -- | |
10 | Replace the TCM. Is the action complete? | -- | -- | |
11 | Check for a poor connection or poor terminal tension at the ECM harness connector. Refer to Electrical Diagnosis in Engine Electrical, and Trouble Shooting Procedures for the proper procedure. Also, refer to Checking Terminal Contact in Engine Control Module Diagnosis . Was a problem found and corrected? | -- | ||
12 |
Important: This vehicle is equipped with a Theft Deterrent System which interfaces with the Engine Control Module (ECM). Program the new ECM with the frequency code of the theft deterrent module that is currently on the vehicle. Replace the ECM. Refer to Engine Control Module Replacement/Programming . Is the action complete? | -- | -- | |
13 |
Is this DTC set? | -- | ||
14 | Were there any additional DTCs noted during the Powertrain OBD System Check that have not been diagnosed? | -- | Go to the applicable DTC table | The System is OK |
