P0324 on Cadillac: How to Diagnose & Fix
Knock Control System Error
1 Cadillac model · 1 documented issue
P0324 on Cadillac by model: symptoms, diagnosis and fix
On some 2016–2019 CT6 vehicles with the 3.6L LGX or 3.0L LGW engine, water-pump noise can accompany DTC P0324. GM PIP5545C directs technicians to compare pump noise and knock-retard readings with the accessory belt installed and removed. If the tests do not support the pump as the source, follow normal service diagnostics.
Common Symptoms
- Service engine soon / check engine light on
- Slight squeak or belt-area noise from the front of the engine
- Noise that may be intermittent and absent at the service visit
How to Fix
Have a qualified technician follow the applicable GM service procedure and PIP5545C diagnostic checks. Replace the water pump only when the noise or knock-retard comparison supports that repair, then re-evaluate. Follow the specified coolant refill procedure. Thermostat replacement and warranty eligibility require separate diagnosis and VIN-specific confirmation; this bulletin does not promise a free repair.
Call to confirm they can assess your vehicle and perform the stated work. Search results do not confirm qualification, eligibility or coverage.
Sources for this issue (1)
P0324 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does P0324 mean on a Cadillac?
P0324 stands for "Knock Control System Error." The PCM has detected an internal fault or an implausible input within the knock-control system. The knock control system uses one or more knock (detonation) sensors to listen for combustion knock/ping and lets the PCM retard ignition timing and adjust fueling to prevent detonation. P0324 sets when the module receives an unexpected knock-sensor signal (for example the circuit reading battery voltage, a full ground, or constant electrical noise) or when the internal knock-processing self-test fails, so the PCM can no longer trust its knock detection. Losing knock control can allow damaging detonation and typically causes the PCM to pull timing as a protective default. On Cadillac it is documented across 1 model: CT6.
What are the most common causes of P0324?
The most common causes of P0324 are: Failed knock (detonation) sensor, Damaged, corroded, or loose knock sensor wiring, connector, or terminals, Short to voltage or short to ground in the knock sensor circuit, Excessive engine mechanical noise mimicking knock (worn components) confusing the system, Internal PCM / knock-processing fault, or PCM needing a software update. The specific cause varies by vehicle.
How much does it cost to fix P0324 on a Cadillac?
Repair costs vary widely with the root cause and Cadillac model; each issue on this page carries its own estimate where one is published.
Looking for P0324 on a different make?
View P0324 across all makes →Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.