Reasons Cited for Code P0412 Or Flash Code 36 from MIL
Posted 2/7/2001
By Brainard Janicki
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“ The solenoid resistance should be 35 to 45 ohms. Make this check with the solenoid unplugged.”
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Vehicle:
1995 Plymouth Laser, Eagle Talon, Chrysler Sebring, Dodge Avenger
Engine:
2.0L DOHC
System:
Emissions/PCM/Fuel
Symptom/Problem:
MIL is illuminated. Code PO412 or a flash code
36 from MIL (manual transmission only).
Our Fix:
The possible reasons for this code setting are: 1) open or shorted EGR solenoid; 2) poor connection at the solenoid connector; 3) open or short in control wire to the PCM; 4) loss of power to the solenoid, such as open wire or a blown fuse; or 5) defective PCM solenoid driver circuit.
First, visually inspect the vehicle to make sure the solenoid is plugged in. Verify the fit and condition of the wiring and connectors. Also inspect the vacuum hose plumbing.
The solenoid resistance should be 35 to 45 ohms. Make this check with the solenoid unplugged.
- If there is an open in the winding, the solenoid will need to be replaced.
- If the solenoid is shorted, it will likely have damaged the driver circuit in the PCM. So, after replacing the solenoid, verify PCM ground operation.
Note: Chrysler recalls No. 7671 and No. 7672 both involve replacing the fuel pressure regulator and disabling this solenoid. Check to see if a recall has been done by looking for a sticker installed near the emissions label. These recalls involve removing the solenoid and capping the aspirator tube as well. Look for the absence of these devices.
If a recall has not been done, check for power (12 volts, key on) on the black/white wire at the solenoid connector. The red/yellow wire is the ground circuit from the PCM. When the PCM requests the valve to not operate or to block operation, the red/yellow wire receives a ground from the PCM. At that time the vacuum is blocked. There will be no EGR operation with the solenoid grounded.
- If there is no power to the black/white power wire, repair the open wire.
- If the red/yellow wire from the PCM is open, repair the open wire.
- If the solenoid is open, or for any other problem, check with the dealer about a possible recall.
ON '92-'94 NISSAN MAXIMA
Posted 2/7/2001
By Paul Kujawa
Intake Camshaft Sprockets
Can Cause Top Engine Noise
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“The common cause of top engine noise on this engine has been the intake camshaft sprockets themselves.”
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Vehicle:
1992 through 1994 Nissan Maxima
Engine:
VE30DE
System:
Engine Mechanical
Symptom:
Top engine noise
This engine has a variable timing control (VTC) system. The intake camshafts are advanced by using oil pressure on the intake camshaft sprockets under certain conditions. Oil pressure to the sprockets is controlled by the VTC solenoids, and the solenoids in turn are controlled by the engine computer (PCM).
The common cause of top engine noise on this engine has been the intake camshaft sprockets themselves. The VTC solenoids are "off" when cam timing is not being advanced. When the VTC solenoids are turned "on" by the PCM, intake camshaft timing is advanced.
To determine if the noise is coming from the VTC sprockets, unplug the VTC solenoids and energize each solenoid. The power supply to the VTC solenoids is the red wire with black tracer (R/B), so jump the battery voltage supply to the solenoid that the R/B wire goes to. When the noise is present at idle, jump the other terminal of the VTC solenoid to ground. This is the yellow wire with green tracer going to it. This will energize or turn "on" the VTC
solenoid and results in pressurizing the sprocket and advancing the cam timing.
Energize one VTC solenoid at a time to see if the noise decreases or goes away. Also energize both solenoids at the same time. Is the noise gone? If it is, a new spring assembly can be installed in the VTC sprocket to tighten it up and correct the problem. The sprocket needs to be pressed apart to replace this spring. Make sure to scribe a mark on the sprocket before pressing it apart so the sprocket can be reassembled in the same alignment, or a noise could result.
Other causes of top engine noise on these engines: timing chain tensioner noise, debris in an oil galley restricting oil to the VTC sprockets or chain tensioner, or from the hydraulic lifters themselves ... although the noise is seldom from the lifters.
Note: Nissan's TSB No. NTB95-022 addresses this issue.
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