New Holland ENG 3136 – Engine Control Unit (ECU): Cold Start Lamp - Excessive Temperature

The Engine Control Module (ECM) has detected an excessive temperature condition on the internal driver circuit that powers the Cold Start Lamp. This is almost always caused by an excessive current draw on the lamp's circuit, such as a short to ground in the wiring harness, a shorted instrument cluster trace, or a faulty bulb drawing too much amperage.

• T7.175
• T7.190
• T7.210
• T8.380
• CR9090
• CX8080
• CX8090
• Magnum 235-340

1. 1

   Visually inspect the wiring harness running from the Engine ECU to the cab/instrument cluster for chafed insulation, pinched wires, or areas rubbing against the chassis.

2. 2

   Disconnect the harness at the ECU and instrument cluster and use a multimeter to check the Cold Start Lamp circuit for continuity to ground (continuity indicates a shorted harness).

3. 3

   Check the cold start indicator bulb for an internal short, or inspect cluster pins for corrosion/internal shorts if using an integrated LED.

4. 4

   Inspect ECU and cluster connectors for pushed-out, bent, or corroded pins that could bridge circuits.

1. 1

   Disconnect Power

   Turn off the ignition and disconnect the negative battery cable to prevent further damage to the ECU.

2. 2

   Isolate the Short

   Based on your multimeter diagnostic checks, isolate whether the short is in the wiring harness or the instrument cluster itself.

3. 3

   Repair the Wiring

   If a short to ground is found in the harness, open the wire loom, locate the damaged wire, and repair it using OEM-approved environmental splices (heat-shrink butt connectors). If the damage is extensive, replace that section of the wiring harness.

4. 4

   Replace the Lamp/Cluster

   If the wiring tests good, replace the faulty cold start lamp bulb. If the lamp is a non-serviceable LED integrated into the dash, the instrument cluster may need to be repaired or replaced.

5. 5

   Reassemble

   Reconnect all harness connectors and the negative battery cable.

6. 6

   Verify Operation

   Turn the ignition key to the ON position (do not start). The cold start lamp should illuminate for a few seconds (depending on ambient temperature) and then turn off.

7. 7

   Clear Codes

   Connect a CNH diagnostic scan tool (EST) and clear the ENG 3136 fault code. Cycle the key to ensure the code does not return.