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Old 06-29-2014, 02:34 PM   #1
AvalonTruck
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More VSV questions

I am chasing the engine light demon. P0446 is the only code. Have a couple of questions.
1)I started (foolishly) by just replacing the VCV next to the charcoal box above rear crossmember... and the dorman 911-605 kinda fit and kinda didn't. The way it did not... is the electrical connector portion. It had the finger actuated release knuckle bump on the bottom, but on the top of the connector there was a plastic tab running it's length on the outside of the connector housing but it was on the wrong side. To get it to plug in mcgyver style, i dremelled it off... now that the engine light came back on i'm wondering if that tab was to denote polarity and perhaps i have to cut and swap the (2) wires leading to the socket on the harness?
2) Since the engine light still comes back on faithfully, I got a haynes manual and some extra vacuum tubing and decided to replace the vacuum tubing one by one. In my poking around i found something real odd... The outermost vacuum hose terminal on VSV for ACIS seemed gunked. I wen't to pull the vacuum tube off and it came off allright, and there was no plastic nipple at all there at the end of the switch housing. Someone apparently broke it off the end of the vacuum switch, and silicone sealed it and the tube together which completely blocked the vacuum tube. Is it possible that the VSV for ACIS might be the cause of P0446, or would it throw a different code?

My guess is it has to be one of the two that's causing it. VSV for EVAP seems ok on the ohmy... Any suggestions?
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Old 06-30-2014, 09:24 AM   #2
Brian R.
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Re: More VSV questions

Unless you have reason to suspect the original VSV was bad, install the original with the correct contacts. There is no way for anyone to guess what the polarity is on the dorman VSV. If you need to replace the VSV, get the correct part.

The DTC for ACIS VSV are P1651/96 and P0660. There may be others, but that's all that I'm aware of.

for P0446:

1. Inspect vacuum hoses and pipes between EVAP (Purge) VSV and Charcoal Canister for leaks.
2. Replace Vapor Pressure sensor VSV and Canister.


Possible Problems
Open or short in VSV circuit for vapor pressure sensor
VSV for vapor pressure sensor
Open or short in vapor pressure sensor circuit
Vapor pressure sensor
Open or short in VSV circuit for EVAP
VSV for EVAP
Vacuum hose cracks, hole, blocked, damaged or disconnected
Charcoal canister cracks, hole, or damaged


1. Check the VSV connector for EVAP, VSV connector for vapor pressure sensor and vapor pressure sensor connector for looseness and disconnection

2. Check the vacuum hose between intake manifold and VSV for EVAP, VSV for EVAP and charcoal canister, charcoal canister and VSV for vapor pressure sensor, and VSV for vapor pressure sensor and vapor pressure sensor. Check these hoses for correct connection, looseness, cracks, holes, damage, and blockage.

3. Check voltage between terminals VC and E2 of ECM connector (4.5-5.5 V). (replace ECM if faulty)

4. Check voltages between terminals PTNK and E2 of ECM connector while applying vacuum to vapor pressure sensor (2.9-3.7 V).

If faulty, check for open and short in harness and connector between vapor pressure sensor and ECM. If ok at this point, replace vapor pressure sensor.

If voltage above is ok, Check VSV for EVAP. When ECM terminal EVP is grounded (ignition "ON"), Air should flow in pipe E (inboard on tube) on VSV and out F (outboard on tube) on VSV (Don't use high pressure air for this test). When EVP is not grounded, air does not flow in E and out F.

5. Check operation of VSV for EVAP. Remove VSV from engine. Check that there is continuity between the two terminals (30-34 ohms). If there is no continuity, replace VSV for EVAP.

Check that there is no continuity between either terminal and body. If there is continuity, replace VSV for EVAP.

Check that air does not flow from inner port (E) to outboard port (F).

Check that air flows from port E to F when you apply battery voltage across terminals. If no air flows, replace VSV for EVAP.

6. Check the vacuum hose between intake manifold and VSV for EVAP, and VSV for EVAP and charcoal canister. Check as above.

7. Check for open or short in harness and connector between EFI main-relay and VSV for EVAP and ECM. If faulty, repair or replace harness or connector. If ok, check and replace ECM.

8. Check VSV for vapor pressure sensor. When ECM terminal TPC is grounded (ignition "ON"), Air should flow in pipe E (inboard on tube) on VSV and out F (outboard on tube) on VSV. When TPC is not grounded, air flows out G (outside of connector).

If ok, check and replace charcoal canister.

If not functioning correctly, check function of VSV for vapor pressure sensor. Remove from engine.
Check that there is continuity between the terminals (33-39 ohms). Replace the VSV if there is no continuity.

Check that air flows from port E (inboard in tube) to port G (side of connector).

Check that air flows from port E to port F (outboard in tube) when battery voltage is applied across terminals. Replace VSV if function is incorrect.

9. If good, Check the vacuum hose between charcoal canister and VSV for vapor pressure sensor, and vapor pressure sensor and VSV for vapor pressure sensor - check as above.

10. Check for open and short in harness and connector between EFI main replay and VSV for vapor pressure sensor and ECM.
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