DTC P2450 (L15B7 (except Si)/L15BA/L15BY) (2020 2021)

DTC P2450:  Evaporative Emission (EVAP) System Purge Line Non-return Valve A Stuck Open

General Description 

Courtesy of HONDA, U.S.A., INC.

Courtesy of HONDA, U.S.A., INC.

Courtesy of HONDA, U.S.A., INC.

Negative side purge flow	Boost side purge flow	Purge back-flow (P2450)	Condition
Flowing	Flowing	OK	Purge line normal, EVAP canister purge valve normal
Flowing	Flowing	NG (P2450)	Non-return valve A abnormal
Not flowing	Flowing	-	Negative side purge line abnormal
Flowing	Not flowing	-	Boost side purge line abnormal
Not flowing	Not flowing	-	Purge line abnormal, EVAP canister purge valve open

The fuel vapor in the fuel tank is temporarily stored in the evaporative emission (EVAP) canister and drawn into the engine through the EVAP canister purge valve. The powertrain control module (PCM) controls the amount of vapor introduced into the engine by varying the duty cycle of the EVAP canister purge valve according to the condition of the engine.

The PCM checks the purge flow conditions on both negative and boost pressure sides. If either side of the purge flow is detected as abnormal, it is determined that there is a clog or disconnection on the abnormal side of the purge line. If both sides of the purge flow are detected as abnormal, it is determined that the purge lines are abnormal or the EVAP canister purge valve is stuck opened.

If non-return valve A is stuck opened, the boost pressure flows back to the fuel tank when purge controlled in boost condition. At the time, the FTP sensor pulse waveform shows opposite phase to the usual phase. The PCM detects a malfunction by calculating the phase time difference, and stores a DTC.

Monitor Execution, Sequence, Duration, DTC Type 

Execution	Once per driving cycle
Sequence	None
Duration	12 seconds* 1 (9.5 seconds)* 2 or more
DTC Type	Two drive cycles, MIL on

*1: L15B7 (except Si) and L15BY

*2: L15BA

Enable Conditions 

Condition	Minimum	Maximum
Low load duration time	10 seconds	-

[ ]: HDS Parameter

Condition	Minimum	Maximum
Engine coolant temperature [ECT SENSOR 1] before EVAP purge control starts	131 deg.F (55 deg.C)	-
MAP value [MAP SENSOR]	-	81 kPa (610 mmHg, 24.0 inHg)
12 volt battery voltage [BATTERY]	10.5 V	-
Fuel trim	0.75	1.47
EVAP canister purge valve duty [EVAP PC DUTY]	30 %	80 %
Fuel feedback	Closed loop at stoichiometric

[ ]: HDS Parameter

Malfunction Threshold 

The FTP sensor pulse phase time difference is 20 milliseconds or more.

Possible Cause 

NOTE:  The causes shown may not be a complete list of all potential problems, and it is possible that there may be other causes.

• Non-return valve A open stuck

Confirmation Procedure 

Operating Condition 

• Start the engine. Hold the engine speed [ENGINE SPEED] at 3, 000 rpm without load (CVT in P or N, M/T in neutral) until the radiator fan comes on.
• Let the engine idle for at least 64 seconds.
• Drive the vehicle at high load for total of at least 11 seconds.
• Turn the vehicle to the OFF (LOCK) mode and leave the vehicle for at least 10 seconds.

With the HDS 

Select the EVAP TEST in the INSPECTION MENU, then select the FUNCTION TEST with the HDS.

Diagnosis Details 

Conditions for setting the DTC 

When a malfunction is detected during the first drive cycle, a Pending DTC is stored in the PCM memory. If the malfunction returns in the next (second) drive cycle, the MIL comes on and a Confirmed DTC and the freeze data are stored.

Conditions for clearing the DTC 

The MIL is cleared if the malfunction does not return in three consecutive trips in which the diagnostic runs. The MIL, the Pending DTC, the Confirmed DTC, and the freeze data can be cleared with the scan tool Clear command or by disconnecting the 12 volt battery.