What does it mean?
P1760 is a Powertrain (engine, transmission, fuel system) fault code. It indicates: TCM Supply Voltage Interrupted (4L30-E) .
Symptoms
- MIL (check engine lamp) on together with a transmission warning lamp
- Transmission resets while driving, briefly dropping to neutral or into limp mode
- Harsh shifts for the first few changes after every restart, as adaptations are lost
- Dash lights flicker or gauges sweep while driving
- Scan tool loses communication with the transmission module intermittently
- Slow cranking or other electrical faults appearing at the same time
Likely causes
- Loose, corroded or under-tightened battery terminals
- Weak or failing battery that drops heavily under load
- Charging system fault producing low or unstable voltage
- Blown fuse, or a fuse sitting loose in a heat damaged fuse holder
- Corroded or loose module ground point on the body or transmission
- Intermittent ignition switch or supply relay contact
- Backed-out or corroded pins in the TCM power connector, or supply wiring damaged by earlier repairs and aftermarket taps
How to fix it
- Load test the battery and check charging system output before anything else
- Clean and tighten the battery terminals and all main ground straps
- Check the transmission fuses and inspect the fuse holders for heat damage and looseness
- Backprobe the TCM power and ground circuits and watch voltage while wiggling the harness
- Perform voltage drop tests on the feed and ground while the system is loaded
- Inspect the TCM connector for pushed-out pins, corrosion and moisture
- Disconnect any aftermarket wiring tapped into the supply, then repair the fault and relearn the adaptive values