For 1990-2009 cars

Table 1: | DTC P1740 Torque Control Circuit (Transmission)
Table 2: | DTC P1740 Torque Control Circuit (ABS/TC)

Engine Controls Components
Engine Controls Schematics
OBD II Symbol Description Notice
Handling ESD Sensitive Parts Notice
Handling ESD Sensitive Parts Notice

### 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.

#### DTC P1740 Torque Control Circuit (Transmission)

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
1 | Did you perform the Powertrain On-Board Diagnostic (OBD) System check? | -- | Go to Step 2 | Go to Powertrain On Board Diagnostic (OBD) System Check
2 |

1. Turn off the ignition.
2. Disconnect the TCM.
3. Turn on the ignition with the engine off.
4. Measure the voltage from the Torque Management Request Circuit in the harness connector to ground with the DVM J 39200 .

Does the DVM indicate the specified voltage?

B+

Go to Step 3

Go to Step 4

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? | -- | Go to Step 7 | Go to Step 6
4 |

1. Turn off the ignition.
2. Disconnect the ECM.
3. Check the harness for continuity of the Torque Management Request Circuit with the DVM J 39200 .

Is continuity indicated?

--

Go to Step 5

Go to Step 8

5 | Check the harness for continuity between the Torque Management Request Circuit and battery ground with the DVM J 39200 . Is continuity indicated? | -- | Go to Step 9 | Go to Step 11
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? | -- | Go to Step 10 | Fault not present. Refer to Diagnostic Aids
7 | Repair the circuit shorted to B+. Is the action complete? | -- | Go to Step 13 | --
8 | Repair the open/high resistance circuit. Is the action complete? | -- | Go to Step 13 | --
9 | Repair the circuit shorted to ground. Is the action complete? | -- | Go to Step 13 | --
10 | Replace the TCM. Is the action complete? | -- | Go to Step 13 | --
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?

--

Go to Step 13

Go to Step 12

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?

--

Go to Step 13

--

13 |

1. Clear the DTCs with the scan tool.
2. Turn off the ignition for 15 seconds.
3. Operate the vehicle within the conditions that are required for this diagnostic to run. Refer to Conditions for Running the DTC.
4. Check for any DTCs.

Is this DTC set?

--

Go to Step 2

Go to Step 14

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

#### DTC P1740 Torque Control Circuit (ABS/TC)

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
1 | Did you perform the Powertrain On-Board Diagnostic (OBD) System check? | -- | Go to Step 2 | Go to Powertrain On Board Diagnostic (OBD) System Check
2 |

1. Turn off the ignition.
2. Disconnect the ABS/TC Module.
3. Turn on the ignition with the engine off.
4. Measure the voltage from the Torque Management Request Circuit in the harness connector to ground with the DVM J 39200 .

Does the DVM indicate the specified voltage?

0V

Go to Step 3

Go to Step 4

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? | -- | Go to Step 7 | Go to Step 6
4 |

1. Turn off the ignition.
2. Disconnect the ECM.
3. Check the harness for continuity of the Torque Management Request Circuit with the DVM J 39200 .

Is continuity indicated?

--

Go to Step 5

Go to Step 8

5 | Check the harness for continuity between the Torque Management Request Circuit and battery ground with the DVM J 39200 . Is continuity indicated? | -- | Go to Step 9 | Go to Step 11
6 |

1. Turn off the ignition.
2. Reconnect the ABS/TC Module.
3. Disconnect the ECM.
4. 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?

--

Go to Step 10

Fault not present. Refer to Diagnostic Aids

7 | Repair the circuit shorted to B+. Is the action complete? | -- | Go to Step 13 | --
8 | Repair the open/high resistance circuit. Is the action complete? | -- | Go to Step 13 | --
9 | Repair the circuit shorted to ground. Is the action complete? | -- | Go to Step 13 | --
10 | Replace the TCM. Is the action complete? | -- | Go to Step 13 | --
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?

--

Go to Step 13

Go to Step 12

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?

--

Go to Step 13

--

13 |

1. Clear the DTCs with the scan tool.
2. Turn off the ignition for 15 seconds.
3. Operate the vehicle with the conditions that are required for this vehicle to run. Refer to Conditions for Running the DTC.
4. Check for any DTCs.

Is this DTC set?

--

Go to Step 2

Go to Step 14

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