For 1990-2009 cars
Engine Controls Components
Gen Control, IAC , Check Gauges Lamp
OBD II Symbol Description Notice
Handling ESD Sensitive Parts Notice
Handling ESD Sensitive Parts Notice

### Circuit Description

The PCM supplies 5 volts on the desired torque circuit to the Electronic Brake and Traction Control Module (EBTCM). The EBTCM toggles this 5 volt signal to a ground in order to produce a duty cycle signal. The signal is proportional to the amount of engine output torque reduction requested by the EBTCM. The EBTCM supplies this signal when it detects a wheel slip. In order to reduce engine output torque, the PCM reduces the amount of spark advance and in some cases, the PCM disables a number of fuel injectors. This diagnostic test checks for a Desired Torque signal failure. If the PCM does not receive the Desired torque signal, this DTC sets.

### Conditions for Running the DTC

• | The traction control has not failed.

• | The engine speed is greater than 500 RPM for 20 seconds.

### Conditions for Setting the DTC

The desired torque signal is not received by the PCM for 3 seconds.

### Action Taken When the DTC Sets

• | The PCM will not illuminate the malfunction indicator lamp (MIL).

• | The PCM will store conditions which were present when the DTC set as Failure Records data only. This information will not be stored as Freeze Frame data.

### Conditions for Clearing the MIL/DTC

• | A History DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.

• | The DTC can be cleared by using the scan tool Clear Info function.

### Diagnostic Aids

Important: Remove any debris from the connector surfaces before servicing a component. Inspect the connector gaskets when diagnosing/replacing a component. Ensure that the gaskets are installed correctly. The gaskets prevent contaminate intrusion.

Important: Do not perform this diagnostic procedure if the customer's concern is not related to the ABS and/or the Traction Control system(s).

The following may cause an intermittent:

• | Mis-routed harness

• | Rubbed through wire insulation

• | Broken wire inside the insulation

### Test Description

The numbers below refer to the step numbers on the diagnostic table.

1. This step determines if the EBTCM is receiving the 5.0 volts from the PCM. Use the connector test kit adaptor J 35616 when probing the EBTCM connector.

2. If no DTCs are set, inspect connections at the EBTCM.

3. This DTC will not report a pass. The scan tool status for this DTC will never report a pass. The scan tool will only display when the diagnostic fails. The repair is not complete if the scan tool indicates that the diagnostic ran and failed.

#### DTC P1571 Desired Torque Circuit

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 | Important: Perform this diagnostic procedure only if the customer's concern is related to the ABS and/or the Traction Control system(s). Refer to Self-Diagnostics in ABS Brakes.

1. Turn OFF the ignition.
2. Disconnect the EBTCM.
3. Turn ON the ignition, with the engine OFF.
4. Probe the Desired Torque circuit using a J 39200 Digital Multimeter that is connected to a good ground.

Does the voltage measure at or near the specified value?

5.0 V

Go to Step 3

Go to Step 4

3 | Important: Verify communication between the scan tool and the EBTCM before you continue with this table. If you can not establish communications, refer to Self-Diagnostics in ABS Brakes. Are any ABS/TCS DTCs or BCM DTCs set? | -- | Go to ABS Brakes or Body and Accessories for further diagnosis | Go to Diagnostic Aids
4 | Probe the Desired Torque circuit using a that is connected to a good ground. Does the voltage measure at or near the specified value? | B+ | Go to Step 7 | Go to Step 5
5 | Probe the Desired Torque circuit using a J 35616-200 Test Lamp that is connected to B+. Does the test lamp illuminate? | -- | Go to Step 8 | Go to Step 6
6 | Test for an open in the Desired Torque circuit. Refer to Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 11 | Go to Step 9
7 | Repair the short to B+ on the Desired Torque circuit. Refer to Wiring Repairs . Did you complete the repair? | -- | Go to Step 11 | --
8 | Repair the short to ground on the Desired Torque circuit. Refer to Wiring Repairs . Did you complete the repair? | -- | Go to Step 11 | --
9 | Inspect for faulty connections at the PCM. Refer to Intermittents and Poor Connections Diagnosis and Connector Repairs . Did you find and correct the condition? | -- | Go to Step 11 | Go to Step 10
10 | Important:: The replacement PCM must be programmed. Refer to Powertrain Control Module Replacement/Programming . Replace the PCM. Did you complete the replacement? | -- | Go to Step 11 | --
11 |

1. Use the scan tool in order to record Fail Records and clear DTCs.
2. Operate the vehicle within the Fail Records conditions.

Does the DTC reset?

--

Go to Step 2

Go to Step 12

12 | Does the scan tool indicate any DTCs set that you have not diagnosed? | -- | Go to applicable DTC | System OK