Overview

This is a set of recommendations for how to troubleshoot potential wiring issues in the vehicle. These issues may be resident in the Transmission Harness, Vehicle Harness, Power Supply Harnesses or other ancillary wiring, depending upon the fault code or condition that is taking place. When troubleshooting wiring, consider that wiring failures can be continuous, intermittent or there may be no failure of the wiring at all.

This procedure describes a visual inspection of wiring and connectors and how to use a volt/ohm meter to inspect for open circuits, short circuits to other wires, and short circuits to ground. Product Diagnostic (PD) Mode is a wiggle-wire test that can be used to detect intermittent open circuit and short circuit conditions that exist while a wire is being moved or flexed. Instructions for PD Mode are included Product Diagnostic (PD) Mode.

Possible Causes

• Various Wires
  • Wiring Shorted to ground, shorted to power or open
  • Bent, spread, corroded or loose terminals
  • Missing or failed connector seals
  • Wiring damaged, pinched or rubbed through

Visual Inspection

• Make sure all connectors are clean and tight.
• Inspect the length of the wiring between connections and look for signs of pinched or chafed wiring.
• When taking a volt/ohm meter reading, inspect for loose terminals, corrosion and bent or spread pins.

  Note: If damage is found to the Transmission Harness, it is recommended that the harness be replaced. Inspect the mating connector for damage and replace, if appropriate. If damage is found to OEM wiring, refer to OEM guide-lines for replacement of wiring and connectors.

• Inspect connectors for debris and contamination. If needed, clean connector and contacts only with an Eaton approved contact and connector fluid.
• When reconnecting, Eaton recommends the use of NyoGel 760G on electrical contacts. Make sure all connectors are clean and tight.
  Notice

  To avoid damaging the TECU, use an Eaton-approved communications adapter and ensure all satellite systems are disabled before updating software.

Use PD Mode for Intermittent Issues

• If there are no Active fault codes, use Product Diagnostic (PD) Mode to diagnose intermittent wiring or connection issues.
• PD Mode allows the user to test loose, degraded or intermittent connection issues using a wiggle wire test.
• See Product Diagnostic (PD) Mode for instructions for using PD Mode.

Recommendations for Using a Volt/Ohm Meter

• Use a quality digital auto-ranging volt/ohm meter.
• When using a volt/ohm meter without auto-ranging capabilities, use the correct range setting for the reading.
• Verify that the battery and fuse are in good working order.
• Some volt/ohm meters have multiple sockets for test leads. Use the correct socket for the type of reading you need.
• Reset the volt/ohm meter to zero before testing by holding the leads together and verifying that the scale shows zero ohms.
• Use the correct pin test adapter for the connector(s) that are being tested. Incorrect test lead sizes may cause permanent damage to connector pins.
• When measuring resistance, be sure that the ignition is off and the circuit is completely powered down.

Example Voltage Readings

Voltage Reading

Verify the voltage measurement is within range. Low voltage readings may be a sign of poor voltage supply or excessive in-line resistance. Pay close attention to whether the reading requires a key-on or key-off condition.

Example Circuit Continuity Readings

Circuit has Continuity

The circuit is complete when the resistance reading is within range. A circuit reading infinite resistance or Open Lead (OL) does not have continuity.

Open Circuit

The circuit is incomplete when the resistance reading is infinite or Open Lead (OL). In cases where resistance readings are greater than 10k ohms, the circuit has some continuity, but is not making good contact. These can generally be treated as an open circuit.

Example End to End Resistance

End to End Resistance is Within Range

The wire has continuity when the resistance reading is within range. A wire reading infinite resistance or Open Lead (OL) does not have continuity.

End to End Resistance is Too High

When the resistance is higher than the acceptable range there is additional resistance in this wire. Check for corrosion, loose or spread pins or damage to the harness.

Open Circuit

The circuit is incomplete when the resistance reading is infinite or Open Lead (OL). Check for wire abrasions, cuts, loose or spread pins and unseated connectors.

Short Circuit to Chassis Ground

Short to Ground

A wire is shorted to ground when the resistance between a non-ground wire and chassis ground shows continuity. Low resistance values (near 0 ohms) indicate a direct short to ground. Higher resistance values may indicate a partial-short.

No Short to Ground

The wire is not shorted to ground when the resistance between a non-ground wire and chassis ground is infinite or Open Lead (OL). This wire has no continuity to chassis ground.

Short to Another Circuit

Two Circuits Shorted Together

When wires from two unrelated circuits show continuity (low resistance) to one another, these circuits are shorted together.

Two Circuits Not Shorted Together

When wires from the two unrelated circuits show an infinite resistance or Open Lead (OL) between one another, these wires are not shorted together.