P1457 EVAP Code Help
#1
P1457 EVAP Code Help
Hi, first time post and in need of some help.
I have a P1457 code on a 1997 Civic EX coupe (D16Y8).
I've followed the flow diagram in the manual.
1. Disconnected vacuum hose from 3 way valve, disconnected canister shut valve. No vacuum
2. A29 to ground. Vacuum
3. Disconnected vacuum hose from canister. 3000rpm I have vacuum
4. Disconnected 2p connector from purge solenoid. 3000rpm I have vacuum.
The vacuum hoses are routed properly and the purge solenoid is good (I tested).
I have 14v+ between the 2p black/yellow and ground when running (no matter the rpms). 0.3v between 2p red/yellow and ground when running. I feel like it's a wiring issue, but the flow diagram ends with replace the purge solenoid that I know is good.
Any help is appreciated. Thanks.
I have a P1457 code on a 1997 Civic EX coupe (D16Y8).
I've followed the flow diagram in the manual.
1. Disconnected vacuum hose from 3 way valve, disconnected canister shut valve. No vacuum
2. A29 to ground. Vacuum
3. Disconnected vacuum hose from canister. 3000rpm I have vacuum
4. Disconnected 2p connector from purge solenoid. 3000rpm I have vacuum.
The vacuum hoses are routed properly and the purge solenoid is good (I tested).
I have 14v+ between the 2p black/yellow and ground when running (no matter the rpms). 0.3v between 2p red/yellow and ground when running. I feel like it's a wiring issue, but the flow diagram ends with replace the purge solenoid that I know is good.
Any help is appreciated. Thanks.
#3
Re: P1457 EVAP Code Help
Gas cap has been replaced. I'm wondering why the blk/yel has voltage across all rpms? Somehow the purge solenoid must get a signal to open at higher rpms.
#4
Re: P1457 EVAP Code Help
How do you know the purge solenoid is good?
Are any other codes thrown?
Aside from P1457, does the car have any problems whatsoever? Any idle problems?
Are any other codes thrown?
Aside from P1457, does the car have any problems whatsoever? Any idle problems?
#6
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#14
Re: P1457 EVAP Code Help
20" Hg is not a deep vacuum. Perhaps you need to pull a deep vacuum (e.g., 27" Hg or more) and test whether it holds or not after 15 minutes.
You also may want to compare vacuum at the IM versus what you read at the EVAP hoses with engine at 3K rpm.
You also may want to compare vacuum at the IM versus what you read at the EVAP hoses with engine at 3K rpm.
#16
Re: P1457 EVAP Code Help
I edited my last post. Deep vacuum is generally between 27 and 30" Hg. For the pump tests, also prolong the time you monitor loss of vacuum to 15 min. It's best to assume at this point that there's a small vacuum leak.
#19
Re: P1457 EVAP Code Help
IM = intake manifold
All vacuum produced by the engine comes from hoses attached to the IM. I'd be curious to compare the vacuum readings at the EVAP hoses to the reading directly at the IM, with the EVAP hose disconnected and the IM nipple blocked.
The cruise control nipple on the IM would be a good place to measure IM vacuum (with engine held at 3K rpm like the EVAP test).
All vacuum produced by the engine comes from hoses attached to the IM. I'd be curious to compare the vacuum readings at the EVAP hoses to the reading directly at the IM, with the EVAP hose disconnected and the IM nipple blocked.
The cruise control nipple on the IM would be a good place to measure IM vacuum (with engine held at 3K rpm like the EVAP test).
#20
Re: P1457 EVAP Code Help
Got it. So I still question how the purge solenoid works. Shouldn't it open at a given rpm? I have constant voltage from idle to 5000rpm at the blk/yel 2p connector. Seems backwards to me that the blk wire is hot. Shouldn't the red/yel have voltage?
#21
Re: P1457 EVAP Code Help
The Red/Yel wire is ground for the purge solenoid and runs to the ECU. The ECU controls the solenoid by controlling ground, not voltage.
#24
Re: P1457 EVAP Code Help
Thanks. So the red/yel from the ECU goes to ground above 154F or with a/c on to open the solenoid? Wondering why I don't have continuity between red/yel and ground above 154F? ...I'm electrically illiterate.
#25
Re: P1457 EVAP Code Help
From my understanding, the first issue appeared at this test step:
It seems that you should not have detected vacuum, but you did.
In addition, if there was a short in the solenoid ground wire, unplugging the purge solenoid connector should have eliminated vacuum in the next test, but it did not. It seems like the purge valve is stuck open.
It seems that you should not have detected vacuum, but you did.
In addition, if there was a short in the solenoid ground wire, unplugging the purge solenoid connector should have eliminated vacuum in the next test, but it did not. It seems like the purge valve is stuck open.