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K. Wiggins
K. Wiggins, ASE Certified Technician
Category: Car
Satisfied Customers: 2440
Experience:  AA in automotive Technology, 15+ years in the trade
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isuzu rodeo: I have a 1996 Isuzu rodeo, with a 3.2L auto 4x4.

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I have a 1996 Isuzu rodeo, with a 3.2L auto 4x4. I keep getting a P0401 Dtc. I replaced the egr valve. I checked continuity of each wire that goes from the egr valve to the pcm. I also replaced the pcm. Still P0401 keeps coming back.
Hello, it would be my pleasure to assist you. The ECM uses signal form the map sensor to control EGR opening and a faulty MAP sensor can also trigger this code. Do you have a scan tool with live data capability so I can help you troubleshoot this further?
Customer: replied 3 years ago.

I do have a scan tool with live data. I replaced the map already, but it didn't work. I also checked the wires from the map to the computer and they are all have continuity.

Thanks it looks as though you've been headed in the right direction so far. If you would click here and look through this trouble tree and let me know if there's anything you may have not tried yet. I will do my best to assist you further.
Customer: replied 3 years ago.

I looked at the diagram. I did not check the evaporative emission canister purge solenoid. Would the Tp sensor and iat sencer that I saw on the diagram make the dtc come on? and what about that evap sensor?

The evap solenoid should have no effect on this. The tps can if it is not going down to 1% when the throttle is released. The IAt us just sharing a ground on that circuit.
Customer: replied 3 years ago.

i have raise the rpm to 2000 for the tps to read 1%. When i release the pedal it goes to back to 0.0% and the rpm is about 850

Sounds like you have a bad TPS my friend. At 2000 RPM it should of read 10-15%
Customer: replied 3 years ago.

So would having the tps read 1% at 2000 rpm cause the P0401 dtc to pop up? Btw what should the tps read at idle?

Yes, what the computer looks for before opening the egr valve is throttle position over 1%, steady manifold vacuum and engine speed over 25MPH. This is due to the fact that when the EGR opens it pretty much cause a vacuum leak and in order for this to not stall the engine all the previously mentioned parameters must be meet.
At idle you should see 0-5% on the TPS.
K. Wiggins and 8 other Car Specialists are ready to help you
Customer: replied 3 years ago.

I have another throttle body i just pluged it in and at 2000 rpm the reading was about 15-20%. Im going to swap it out now.

I think this might solve the problem. If i have any problems i will def follow up. Thank you!

Sounds good, just let me know. I'll be on line for several ore hours today