CAT 32 Fault Code: Engine Injector Cylinder #03 : Erratic, Intermittent, or Incorrect
Engine Injector Cylinder #03 : Erratic, Intermittent, or Incorrect · ai-assisted, editor-reviewed · Last updated 2026-07-13
TL;DR
CAT code 32, SPN 653 FMI 2, means the ECM detects an erratic, intermittent, or incorrect signal from the cylinder #3 injector solenoid. The ECM logs the code and keeps energizing the solenoid, so the engine keeps running, but the injector circuit needs to be checked, especially wiring and connectors that may only fail under vibration or heat.
Medium severity. The engine keeps running because the ECM continues to energize the injector solenoid, so this is not an immediate shutdown code. But an erratic injector on one cylinder can cause rough running, power loss, or misfire-like symptoms, and it should be diagnosed before the underlying wiring or injector fault gets worse.
What does CAT error code 32 mean?
CAT code 32 corresponds to SPN 653, FMI 2, and is described as Engine Injector Cylinder #3: Erratic, Intermittent, or Incorrect. These engines use Electronic Unit Injectors (EUI) that are electronically controlled, with each injector containing a solenoid. The ECM sends 105 V pulses to each injector solenoid at the proper time and duration for the current engine load and speed.
When the ECM detects that the signal or response from the cylinder #3 injector solenoid is erratic, intermittent, or incorrect, it logs code 32. The ECM does not de-energize the solenoid when this happens, it continues to energize it, so the engine keeps operating while the fault is recorded.
Problems with an injector solenoid typically show up when the engine is warmed up and under vibration, such as during heavy loads. This points toward wiring and connector issues that only appear under heat and vibration, rather than issues visible with the engine cold and idling.
Common causes of 32
- Failed injector on cylinder #3
- Wiring between the ECM and the valve cover
- Wiring under the valve cover for the injector harness
- Plugged oil outlet port on the exhaust valve rocker arm
How to troubleshoot CAT 32: first checks
- Bring the engine up to normal operating temperature before testing, since injector solenoid problems typically occur when the engine is warmed up and under vibration or heavy load
- Carefully inspect the wiring and connectors between the ECM and the valve cover, and under the valve cover for the injector harness, for damage, chafing, or loose connections
- Watch for wiring or connector problems that only appear during vibration, so wiggle-test harnesses and connectors while the engine is running under load if it is safe to do so
- Check the oil outlet port on the exhaust valve rocker arm for cylinder #3 for blockage
- Inspect the cylinder #3 injector itself for signs of failure once wiring and the rocker arm oil passage have been checked
How the code clears
This is described as a -2 style intermittent/erratic code rather than a -7 code, and no separate reset or clearing step is listed for FMI 2 itself. The Fuel System Verification Test is specifically called out as required to clear a -7 code, not this code, so that test applies to a different FMI, not to code 32 directly. Once the wiring, connector, rocker arm oil port, and injector have been inspected and any faults corrected, the code should stop logging on its own as the ECM sees a stable signal.
Frequently asked questions
What does CAT fault code 32 mean?
It means the ECM has detected an erratic, intermittent, or incorrect signal from the cylinder #3 injector solenoid, logged as SPN 653, FMI 2. The engine keeps running because the ECM continues to energize the solenoid.
Will the engine shut down when code 32 is active?
No. The code is logged and the ECM continues to energize the injector solenoid. The engine keeps operating, but the underlying wiring or injector issue should still be diagnosed.
Why does this code only show up sometimes?
Injector solenoid problems typically occur when the engine is warmed up and under vibration from heavy loads. Wiring and connectors can have faults that only appear under those conditions, so the code may not be present at cold idle.
What should I check first for code 32?
Start with the wiring between the ECM and the valve cover, and the wiring under the valve cover for the injector harness. Also check the oil outlet port on the exhaust valve rocker arm for cylinder #3 for a blockage, and inspect the injector itself.
Do I need to run the Fuel System Verification Test for code 32?
That test is specifically required to clear a -7 code, not this FMI 2 code. For code 32, no separate clearing procedure is listed, so focus on inspecting wiring, the rocker arm oil port, and the injector.
Can a plugged oil passage really cause an injector fault code?
Yes. A plugged oil outlet port on the exhaust valve rocker arm is listed as one of the possible causes of this code, alongside wiring issues and a failed injector.