Cummins fault code · Auxiliary inputs, outputs and generator controls

Cummins fault code 528

Auxiliary Alternate Torque Validation Switch: erratic or intermittent signal

J1939 SPN93
FMI2
LampAmber warning lamp
SystemAuxiliary inputs, outputs and generator controls

What it means

Cummins' description: Auxiliary Alternate Torque Validation Switch - Data erratic, intermittent or incorrect.

SPN 93 is Engine Net Brake Torque. FMI 2 means the signal is jumping around, dropping in and out, or doesn't make sense compared to other readings.

These codes cover extra inputs and outputs the ECM controls or monitors: auxiliary temperature and pressure sensors, relays, lamps, and generator or equipment controls on off-highway and generator engines.

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.

How serious is it?

Green, yellow, red: three ways this can look

The same code can be a quick fix or a reason to shut down. Match your situation to the closest example.

Green

Keep an eye on it

An auxiliary code for an accessory that isn't used on your truck.

Yellow

Schedule a repair

An accessory, gauge or lamp not working with the code set. Fix the circuit when convenient.

Red

Stop and get help

The code is tied to a shutdown or protection relay. Have it checked before relying on that protection.

Common causes

The sensor reading itself is out of range or the condition is real, so look at the system:

  • Real reading from the equipment the input is monitoring

What you can check before calling

  • Find out what the auxiliary input is wired to on your truck or equipment
  • Check connectors and relays in that circuit

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

Engines and sources

Listed by Cummins for: QSX 15, QSG 12. 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.

Look up another code

Cummins fault code (like 1922), J1939 SPN and FMI (like SPN 3251 FMI 0), or an OBD-II code (like P0420).

Questions

What does Cummins fault code 528 mean?

Cummins fault code 528 is J1939 SPN 93 FMI 2: Auxiliary Alternate Torque Validation Switch - Data erratic, intermittent or incorrect. In plain terms: auxiliary alternate torque validation switch: erratic or intermittent signal.

Can I keep driving with Cummins code 528?

Usually for a short time, if the engine runs normally and no other warnings are on. Get it diagnosed soon, because many amber codes lead to a derate if ignored. Look at the green, yellow and red examples on this page to judge your situation.

What is the SPN and FMI for Cummins code 528?

SPN 93 identifies the part or system (Engine Net Brake Torque). FMI 2 describes the type of failure: erratic or intermittent signal.

What usually causes Cummins code 528?

The most common causes are: real reading from the equipment the input is monitoring.

Diesel down in the Midlands?

We work on Cummins-powered pickups, vans and medium-duty trucks across Lexington, Columbia and the Midlands, on site at your yard or roadside.

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