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Gm Tech (Cam)
Gm Tech (Cam), Saturn Mechanic
Category: Saturn
Satisfied Customers: 29570
Experience:  GM Grand Master Technician 2007. 14 years experience.
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2001 saturn: I replaced the air injection pump..used one..pump works

Resolved Question:

I got a 401 code on my 2001 saturn SL1 , I replaced the air injection pump, silenod and valve, with a used one, the pump works, I reset the codes and thought it was fixed, but it came on again. any suggetions on what to check?
Submitted: 7 years ago.
Category: Saturn
Expert:  Gm Tech (Cam) replied 7 years ago.

Welcome. This is not an airpump code, it is an EGR Code. Below is the information on the code.

DTC P0401
Object Number: 871361  Size: MF

The exhaust gas recirculation (EGR) valve consists of a pintle valve which moves by the use of an internal solenoid and an internal position sensor (potentiometer) used to determine pintle valve position. The powertrain control module (PCM) controls the solenoid by supplying it ignition voltage whenever exhaust gas needs to be recirculated into the intake manifold. The PCM monitors the EGR solenoid and position sensor circuit for correct voltage levels at certain times. The PCM also monitors the flow of exhaust gas through the EGR valve by using the manifold absolute pressure (MAP) sensor. During deceleration, the EGR valve is normally closed. However, the PCM will run a flow test by opening the EGR valve and monitoring the change in the MAP signal voltage. DTC P0401 sets when the change in the MAP signal voltage is below a certain threshold when the EGR valve is being commanded ON during the deceleration.

DTC Parameters

DTC P0401 will set if the PCM determines EGR flow to be restricted based on engine speed and barometric pressure using the MAP sensor when:

The engine speed is between 1250-2600 RPM.
The vehicle speed is greater than 56 km/h (35 mph).
The throttle position (TP) angle is 0 percent (vehicle in decel).
The engine coolant temperature (ECT) is greater than 70°C (150°F).
No cam, crankshaft position (CKP), ECT, EGR solenoid, 5-volt reference, idle air control (IAC), intake air temperature (IAT), MAP, misfire, PCM internal fault, TP or vehicle speed DTCs have been set.

DTC P0401 diagnostic runs once per ignition cycle for 1 second during deceleration once the above conditions have been met.

DTC P0401 is a type A DTC.

Diagnostic Aids

Verify the MAP sensor reads correctly at idle (between 1-1.5 volts). If the MAP sensor is skewed or faulty, DTC P0401 may set.

The most likely cause of this DTC is carbon buildup around the EGR valve or a blocked EGR passage.

Remove the EGR valve and check for a blocked passage and for carbon buildup around the EGR pintle valve. Clean or replace the EGR valve and/or clean EGR passage.

Customer: replied 7 years ago.
let me double check my code, because it said secondary air pump be right back, the code is a 410 code, s0rry about that
Customer: replied 7 years ago.
I am sorry I meant the code is a 410 code, I changed the pump with a used one and also the valve and seleinode that was with it. it is a 2001 saturn sl1. I erased the codes and after 50 miles or so the light came back on.
Expert:  Gm Tech (Cam) replied 7 years ago.

Ok, have you checked that the pump is running and the hoses from the pump to the exhuast? Have you checked the wiring? Did you check the fuse for the air pump?


Customer: replied 7 years ago.
I checked the pump before I hooked it up, and it ran
Expert:  Gm Tech (Cam) replied 7 years ago.

Did you check the fuse in the car ?Perhaps the old pump blew the fuse and the new pump will not run because of that.

Customer: replied 7 years ago.
I will check the fuse, is it in the car or under the hood? before i installed the other pump I plugged it in and it ran.
Expert:  Gm Tech (Cam) replied 7 years ago.
I am sorry for the delay, I had my youth group banquet last night. THe fuse is a 30 amp fuse in the under hood fuse block.
Gm Tech (Cam) and other Saturn Specialists are ready to help you
Customer: replied 7 years ago.

ok , thanks I will check that. Yesterday the car got a massive antifreeze leak somewhere on the back of the engine, it pours right out as fast as you can put it in, checked all the hoses and I believe it might be the intake gasket, I will check the fuse and get back to you.

I used this site before for a problem I had with a truck and it was super, I tipped the person for helping me.


I will get back to you in a bit about the fuse.




Customer: replied 7 years ago.

I have a guy putting in the intake gasket, do you believe that the intake gasket may make the pump throw a code? Let me know, I have to leave for work in about a half hour. I will accept the answer, after I recieve it and if it still does it I will hop on again.




Customer: replied 7 years ago.

hi please read my last reply about the intake gasket, do you think a leaky intake gasket would maybe cause the code?: I will accept but could you please answer this part of question , thanks



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Expert:  Gm Tech (Cam) replied 7 years ago.
Sorry Bruce, I have been busy. The P0410 is the exhaust side so I can't see how a leaking intake gasket would cause that code.
Customer: replied 7 years ago.
Thanks, XXXXX XXXXX gasket gets done I will check a few things out and start a new post.