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Discussion Starter · #1 ·
Can u swap an ecu to clear codes. i have a p0443 code which is a purge volume control valve which is attached to the charcoal canister, well i've replaced the valve, check engine light still on and still spitting out same code. i changed the charcoal canister and same issue, so i was thinking that maybe my ecu has malfunctioned and not recognizing the work that was completed for this code, so if i could swap out ecu's would this help or damage my car, please help. thank you. patrick
 

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Here is what the B14 Factory Service Manual has to say about P0443:

Malfunction is detected when:
An improper voltage is sent to the ECM through EVAP canister purge control solenoid valve.
Possible Causes:
- Harness or connectors (The EVAP canister purge control solenoid valve circuit is open or shorted)
- EVAP canister purge control solenoid valve

Malfunction is detected when:
EVAP canister purge control valve does not operate properly (stuck open)
Possible Causes:
- EVAP canister purge control valve
- EVAP canister purge control solenoid valve
- Vacuum hoses clogged or disconnected
- EVAP control system pressure sensor

Which one of these did you replace? The EVAP canister purge control valve has a disc-shaped top with a small connector for a vacuum line, and two larger hose connectors at a right angle to each others below. The EVAP canister purge control solenoid valve is a box-shaped gizmo with an electrical connector on top, two hose connectors at the other end pointing up, and a third hose connector below the electrical connector.

The EVAP control system pressure sensor is a box-shaped gizmo with an electrical connector on one end and a hose connector on a pedestal pointing in the same direction as the electrical connector.

Lew
 

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Discussion Starter · #5 ·
I replaced the valve that goes into the evap canister which is the evap volume control solenoid valve(this valve only has one hose and an electrical connection), maybe i need to replace the other valves? thank you for the indepth reply. patrick
 

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Discussion Starter · #6 ·
new question, for an electrical harness or connector would i just need to cut new wire from the old harness and where could i find a new harness, dealership, junkyard?
 

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p-wetz said:
new question, for an electrical harness or connector would i just need to cut new wire from the old harness and where could i find a new harness, dealership, junkyard?
Generally, the harness and connectors don't need to be replaced. Usually if this kind of problem exists, it is a bad contact in a connector due to corrosion which is cured by disconnecting and reconnecting it.

You can check a harness by disconnecting both ends and checking each conductor with an ohm-meter. This is very time-consuming, and usually done as a last resort. If you must replace a harness, it is cheapest to pull one from a car in a salvage yard. Since the wires from the EVAP system are buried in a large cable which goes to the ECU, you would have to replace the entire ECU harness since that is easier than separating the EVAP wires out.

Hopefully I have convinced you that you don't want to consider replacing the wiring.

Lew
 

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Discussion Starter · #8 ·
yes you have but what should i do? replace the ecm with one from a salvage yard, theres a 97 sentra at a yard near my house with only 30,000 miles on it so i no the ecm is fairly new, and maybe it's my ecm that needs replaced. i used a multi meter on the harness and one side of the harness i get 12 volts other side i get nothing is this side the ground, help if you can i have already spent 68.00 for the vavle and 150 for the canister, but i want to sell the car but anyone who sees the check engine light will not understand that it has no effect on the cars driveability. so if you could help in any way please do. thank you patrick
 

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p-wetz said:
yes you have but what should i do? replace the ecm with one from a salvage yard, theres a 97 sentra at a yard near my house with only 30,000 miles on it so i no the ecm is fairly new, and maybe it's my ecm that needs replaced. i used a multi meter on the harness and one side of the harness i get 12 volts other side i get nothing is this side the ground, help if you can i have already spent 68.00 for the vavle and 150 for the canister, but i want to sell the car but anyone who sees the check engine light will not understand that it has no effect on the cars driveability. so if you could help in any way please do. thank you patrick
You don't need a new ECM. Pull the EVAP parts from the 97 and replace yours with them. Then reset the ECU by disconnecting the battery overnight. If the Check Engine light comes on again, pull the codes to see if it is the same fault.

Lew
 

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Discussion Starter · #10 ·
i will try that but besides the evap volume control solenoid valve and the canister what other parts should i replace, im going out to my car right now to disconnect all the harnesses back by the valve and im going to clean all the harness with electrical cleaner to see if this helps any. thanks again patrick
 

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p-wetz said:
i will try that but besides the evap volume control solenoid valve and the canister what other parts should i replace, im going out to my car right now to disconnect all the harnesses back by the valve and im going to clean all the harness with electrical cleaner to see if this helps any. thanks again patrick
Look at post #4 above. It lists all the parts involved. The cannister is not one of them.

Lew
 
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