Cummins fault code 697

What it means

Cummins' description: Engine ECU Temperature Sensor Circuit - Voltage above normal, or shorted to high source.

SPN 1136 is Engine ECU Temperature. FMI 3 means the voltage on the circuit is higher than possible for a good sensor, usually an open signal wire, a short to a power wire, or a failed sensor.

The engine ECM talks to the transmission, ABS, dash and aftertreatment modules over the J1939 data network. These codes mean the ECM itself, its calibration, or its communication with other modules has a problem.

What the lamp means

An amber (yellow) warning lamp means the engine can usually keep running, but the fault should be repaired soon, ideally the same day.

Common causes

FMI 3 is an electrical or signal fault, so start with the circuit:

• J1939 network wiring damaged or shorted
• Missing or failed terminating resistor
• Corroded connector at a module
• Another module on the network failed or lost power
• Low battery voltage during cranking

If the circuit checks out, the reading may be real. Other possibilities: eCM calibration doesn't match the vehicle or another module; eCM internal failure.

What you can check before calling

• Note which other systems acted up: gauges, transmission, ABS
• Check for recent electrical work or aftermarket devices plugged into the diagnostic port
• Check batteries and grounds

Clearing the code without fixing the cause usually brings it right back, and on emissions systems it can restart derate timers.

Engines and sources

Cummins uses the same fault code numbers across its electronic engines, including on-highway models like the ISB/B6.7, ISL/L9 and ISX/X15, though not every code applies to every engine or software level. Source: Cummins Tier 4 Fault Codes. Always confirm with Cummins service information (QuickServe) for your engine serial number.