Electrical Pretest Gen1 ECA (TRTS0940)

UltraShift PLUS

TRTS0940 EN-US

November 2023 - A

Electrical Pretest Gen1 ECA

Overview

This procedure provides a basic test of the vehicle electrical system. A well-functioning electrical supply is required for proper operation of the UltraShift PLUS transmission.

This test verifies the vehicle batteries are fully charged, proper battery and ignition voltage are being supplied to the transmission components, and the electrical system can supply proper voltage and current when under load.

Fault codes that set for a specific transmission give additional information about performance issues detected on that vehicle. If a unit has an Active fault code, or repeated occurrences of an Inactive fault code, refer to the troubleshooting procedure for that fault code. Certain fault code troubleshooting procedures require completion of the Troubleshooting Pretest. Some electrical system failures may cause performance problems without setting a fault code.

Detection

None

Conditions to Set Fault Code Active

None

Fallback

None

Conditions to Set Fault Code Inactive

None

Possible Causes

Vehicle Batteries

- Internal failure

Vehicle Charging System

- Charging system failed
- Alternator-Generator failed

Vehicle Harness

- Poor power or ground supply to Transmission Electronic Control Unit (TECU)
- Bent, spread, corroded or loose terminals
- Wiring shorted to ground, shorted to power or open
- Improperly seated or missing 30-amp fuse

Vehicle Power and Ground Supply to ECA

- Poor power or ground supply to ECA
- Wiring shorted to ground, shorted to power or open
- Improperly seated or missing 40-amp fuse
- Bent, spread, corroded or loose terminals

Transmission Harness

- Wiring shorted to ground, shorted to power or open
- Bent, spread, corroded or loose terminals

Additional Tools

Battery load testing equipment (see OEM for specific recommendations)

Component Identification

1. 38-Way Vehicle Harness Connector

2. Transmission Electronic Control Unit (TECU)

3. ECA Shield

4. 4-Way Diagnostic Connector

5. Electronic Clutch Actuator (ECA)

6. 3-Way ECA Connector

_Graphics/LineArt/TRTS0940_EPT_Wiring1.png

1. Transmission Electronic Control Unit (TECU)

2. 4-Way Diagnostic Connector

3. 40-amp Fuse

4. In-line Fuse Holder

5. 3-Way ECA Connector

6. Electronic Clutch Actuator (ECA)

_Graphics/LineArt/TRTS0940_EPT_Wiring2.png

1. Transmission Electronic Control Unit (TECU)

2. 38-Way Vehicle Harness Connector

3. 30-amp Fuse

4. In-line Fuse Holder

Electrical Pretest Gen1 ECA

Purpose:Inspect the batteries, in-line fuse and power and ground supplies to the TECU.

Key off.
Measure voltage across all batteries. Record reading(s) in table.
Inspect starter, battery terminals and transmission 30-amp in-line fuse holder connections for damage and bent, spread, corroded or loose terminals.
Visually inspect Vehicle Harness between the power supply and the TECU for signs of rubbing or chafing to the wiring.
Note: Some chassis use a power and ground distribution block separate from the battery or may route power and ground to the starter. Be sure to clean and inspect connections at this location and at the battery.

If damage is found, repair or replace wiring per OEM guidelines, Go to Step B

If no damage is found, Go to Step B

Battery Voltage

Purpose:Verify power and ground supply to the ECA.

Key off.
Inspect the ECA 40-amp In-line Fuse Holder Connections for damage and bent, spread, corroded or loose terminals.
Visually inspect ECA Power Supply Harness between the power supply and the ECA for signs of rubbing or chafing to the wiring.
Note: Some chassis use a power and ground distribution block separate from the battery or may route power and ground to the starter. Be sure to clean and inspect connections at this location and at the battery.

If damage is found, refer to OEM guidelines for repair or replacement of battery power and ground supply to ECA, Go to Step V

If no damage is found, Go to Step C

Purpose:Perform a Load Test on each vehicle battery.

Key off.
Notice
Allow 2–3 minutes for the TECU to perform a complete power-down sequence before proceeding.
Load test each vehicle battery per OEM specifications. Record reading(s).

If all batteries pass the Load Test, Go to Step D

If any battery does not pass the Load Test, refer to OEM guidelines for repair or replacement of batteries. D

Battery	Voltage Drop	Load Test Status (Pass/Fail)
1
2
3
4
5

Purpose:Verify voltage supply to the TECU through the 4-Way Diagnostic Connector.

Reconnect all harnesses and connectors.
Key on with engine off.
Remove connector cover of 4-Way Diagnostic Connector on the Transmission Harness.
Measure voltage between Pin B (Service Battery positive) and Pin C (Service Battery negative). Record reading(s).
Warning
Do not Load Test the power supply through this connection.
Compare reading(s) in table.

If readings are in range, Go to Step G

If readings are out of range, Go to Step E

Pins	Range	Reading(s)
B to C	Within 1.2 V of Battery Voltage

Purpose:Verify battery voltage at the TECU.

Key off.
Disconnect 38-Way Vehicle Harness Connector from TECU.
Inspect connector body for damage and bent, spread, corroded or loose terminals.
Measure voltage between 38-Way Connector Pin 38 (Battery positive) and Pin 36 (Battery negative). Record reading(s).
Compare reading(s) in table.

If readings are in range, Go to Step F

If readings are out of range, refer to OEM guidelines for repair or replacement of battery power and ground supply to TECU. Go to Step V

Pins	Range	Reading(s)
38 to 36	Within 1.2 V of Battery Voltage

Purpose:Verify continuity and check for short to ground of service battery voltage circuits between the TECU and 4-Way Diagnostic Connector.

Key off.
Disconnect 38-Way Transmission Harness Connector from TECU.
Inspect connector body for damage and bent, spread, corroded or loose terminals.
Measure resistance between Pin 31 and Pin C. Record reading(s) in table.
Measure resistance between Pin 17 and Pin B. Record reading(s) in table.
Measure resistance between Pin B and ground. Record reading(s) in table.
Compare reading(s) in table.

If readings are out of range, replace Transmission Harness. Go to Step V

If readings are in range, replace TECU. Go to Step V

Pins	Range	Reading(s)
31 to C	0.0–0.3 Ohms
17 to B	0.0–0.3 Ohms
B to Ground	Open Circuit (OL)

Purpose:Verify ignition voltage to the TECU through the 4-Way Diagnostic Connector.

Key off.
Reconnect all harnesses and connectors.
Key on with engine off.
Remove connector cover of 4-Way Diagnostic Connector on the Transmission Harness.
Measure voltage between Pin A (Service Ignition positive) and Pin C (Service Battery negative). Record reading(s).
Warning
Do not Load Test the power supply through this connection.
Compare reading(s) in table.

If readings are in range, Go to Step J

If readings are out of range, Go to Step H

Pins	Range	Reading(s)
A to C	Within 1.2 V of Battery Voltage

Purpose:Verify ignition voltage at the TECU.

Key off.
Disconnect 38-Way Vehicle Harness Connector from TECU.
Verify connector is free from any corrosion; the terminals are not bent, spread or loose; and there is no damage to the connector body.
Key on with engine off.
Measure voltage between 38-Way Connector Pin 35 (Ignition positive) and Pin 36 (Battery negative). Record reading(s) in table.
Compare reading(s) in table.

If readings are in range, Go to Step I

If readings are out of range, refer to OEM guidelines for repair or replacement of ignition voltage supply. Go to Step V.

Pins	Range	Reading(s)
35 to 36	Within 1.2 V of Battery Voltage

Purpose:Verify continuity and check for short to ground of service ignition circuit between the TECU and 4-Way Diagnostic Connector.

Key off.
Disconnect 38-Way Transmission Harness Connector from TECU.
Inspect connector body for damage and bent, spread, corroded or loose terminals.
Measure resistance between Pin 25 and Pin A. Record reading(s) in table.
Measure resistance between Pin A and ground. Record reading(s) in table.
Compare reading(s) in table.

If readings are out of range, replace Transmission Harness. Go to Step V

If readings are in range, replace TECU. Go to Step V

Pins	Range	Reading(s)
25 to A	0.0–0.3 Ohms
A to Ground	Open Circuit (OL)

Purpose:Verify condition of 3-Way ECA Connector.

Key off.
Disconnect 3-Way ECA Connector.
Verify connector is free from any corrosion; the terminals are not bent, spread or loose; and there is no damage to the connector body.
Confirm the 3-Way Connector has a seal plug in Cavity A.

If damage is found to the ECA Power Harness, refer to OEM guidelines for repair or replacement of the ECA Power Harness. Go to Step V

If damage is found to the ECA side of the 3-Way ECA Connector, replace ECA. Go to Step V.

If no damage is found, Go to Step K

Purpose:Verify battery voltage at ECA.

Key off.
Measure voltage between 3-Way ECA Connector Pin C (Battery positive) and Pin B (Battery negative). Record reading(s) in table.
Compare reading(s) in table.

If readings are in range, Go to Step L

If readings are out of range, refer to OEM guidelines for repair or replacement of the ECA Power Harness. Go to Step V

Pins	Range	Reading(s)
C to B	Within 1.2 V of Battery Positive (+)

Purpose:Verify polarity of battery voltage at ECA.

Key off.
Measure voltage between 3-Way ECA Connector Pin C (Battery positive) and ground. Record reading(s) in table.
Compare reading(s) in table.

If sent here from a Fault or Symptom Isolation Procedure and readings are in range, Electrical Pretest complete. Return to the Fault or Symptom Isolation Procedure for further diagnostic instructions.

If readings are in range, Go to Step V

Pins	Range	Reading(s)
C to Ground	Within 1.2 V of Battery Positive (+)

Purpose:Verify Electrical Pretest.

Key off.
Reconnect all connectors and verify that all components are properly installed.
Key on with engine off.
Clear fault codes using ServiceRanger.
Drive vehicle and attempt to reset the code or duplicate the previous complaint.
Check for fault codes using ServiceRanger.

If no fault codes set Active, test complete.

If a fault code sets Active, troubleshoot per Fault Code Isolation Procedure Index.