The coolant level sensor uses a floating ball with a magnetic switch. When the coolant level is full, the
float will rise and the magnet will pull the level switch open. This allows a 5 V signal at ECM Pin X3–4.
When the level is low, the switch will close and ECM Pin X3–4 will be 0 V.

Fault Detection / Management
The ECM continuously monitors the ECL circuit for in-range faults. The ECM does not detect open or
short circuits in the ECL system. When the ECM detects an in-range fault, DTC 236 will be set.

ECL Diagnostic Trouble Codes (DTCs)
DTCs are read using the EST or by counting the flashes from the amber and red ENGINE lamp.

DTC 236
ECL switch circuit fault
• DTC 236 is set when the ECM detects an in-range fault voltage and the voltage is between 3.4 V and 4.3 V at ECM      Pin X3–4 for more than 2.0 seconds.
• DTC 236 is set when a high resistance connection or intermittent short to ground in the circuit exists.
• DTC 236 will not illuminate the red ENGINE lamp.
If the condition is intermittent, the DTC will be logged as inactive.

• EST with MasterDiagnostics® software
• EZ-Tech® interface cable
• Digital Multimeter (DMM)
• Breakout Box