DTC P1378-00: Pre-ignition Detected [12/2021 - ]: Description

If sudden early ignition (pre-ignition) occurs continuously in a short period of time, a DTC is stored. This pre-ignition is a phenomenon inherent in boosted engines. Atomized engine oil and detached deposits (carbon) cause ignition and promote knocking during low-speed, high-output operation. This is higher pressure knocking than normal knocking.

Pre-ignition is detected by the knock control sensor.

When pre-ignition occurs, the ECM limits output to suppress the pre-ignition. If pre-ignition occurs continuously, the fuel may be cut in some conditions, which may cause vehicle behavior that seems similar to hesitation or shift shock. This is normal engine control and not a malfunction.

As pre-ignition cannot be detected if a knock control sensor malfunction occurs, the same fail-safe control occurs as for strong knock detection.

HINT:

When this DTC is stored, the ECM enters fail-safe mode.
During fail-safe mode, the ECM limits the output.
Fail-safe mode continues until the ECM clears the DTC.

DTC No.	Detection Item	DTC Detection Condition	MIL	DTC Output from	Priority	Note
P1378-00	Pre-ignition Detected	2 or more continuous pre-ignition prevention fuel-cut control operations (1 trip detection logic). Continuous pre-ignition prevention fuel cut control: Sudden early ignition (pre-ignition) occurs 5 times or more continuously in a short period of time.	-	Engine	B	SAE: P1378

Trouble Area
Ignition system	Ignition malfunction of ignition coil assembly or spark plug
Fuel injection system	Decrease in fuel injection volume (for Direct Injection)
Lubrication system	High oil consumption Dilute/deteriorated oil Additive
Fuel system	Diesel fuel contamination Addition of fuel additives Fuel pump assembly Low quality fuel
Engine related	Accumulated deposit (in combustion chamber)
Intake system	Air leaks
Exhaust system	Clogged exhaust system component

HINT:

As strong knocking due to pre-ignition may be caused by multiple superimposed factors, it is important to comprehensively investigate all possible causes.
The risk of this occurring is increased if driving up a steep incline while towing when fixed in low gear, as low-speed, high-output operation occurs.