# P0402 OBD-2 Trouble code



## tppcamaroz (Nov 21, 2005)

_My engine light just came on last week.I brought my truck into Autozone to have the run the trouble code.The trouble code was P0402 Exhaust Gas Recirculation Flow (EGR Excessive detected.I've had symptoms of when it rains my truck sputters out when taking off from a traffic light.Its been like that for about 1 year.Do I need to replace the EGR? Or do I need to clean it? I recently had repairs done on my 4cyl hardbody.I got new wires,plugs,air filter,air recharged,air condenser,air dryer.Would any of these cause the Engine light to come on? I would't think so??

Also, my condenser keepsmaking a squealing noise.Is it okay to run my A/c when it squeals? Is this mean my AC condensers going out?

Thanks!! _


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## smj999smj (Jan 1, 2006)

What year Hardbody? There was an updated EGR valve made available for some year Hardbodies and could be your issue as symptoms are similar. I believe it was for 96-97. Sounds like the EGR is staying open, which could be a mechanical problem with the EGR valve, debris stuck in the seat, or vacuum staying applied to the EGR diaphragm when it shouldn't be.

I think when you say "condensor," you actually mean "compressor." The condensor is the part that sits just in front of the radiator. The compressor is the part that bolts to the engine and is driven by a drive belt. If it's "squeeling," it usually means the drive belt is loose or glazed, but could also be a bad idler pulley bearing, as well. Have the belt checked.


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## tppcamaroz (Nov 21, 2005)

smj999smj said:


> What year Hardbody? There was an updated EGR valve made available for some year Hardbodies and could be your issue as symptoms are similar. I believe it was for 96-97. Sounds like the EGR is staying open, which could be a mechanical problem with the EGR valve, debris stuck in the seat, or vacuum staying applied to the EGR diaphragm when it shouldn't be.
> 
> I think when you say "condensor," you actually mean "compressor." The condensor is the part that sits just in front of the radiator. The compressor is the part that bolts to the engine and is driven by a drive belt. If it's "squeeling," it usually means the drive belt is loose or glazed, but could also be a bad idler pulley bearing, as well. Have the belt checked.



My hardbody is a 1997 king cab, Yeah, its my compressor thats squelling,I will have to get it checked.Thanks for the helpful information.


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## smj999smj (Jan 1, 2006)

Classification:
EC97-039

Reference:
NTB97-100

Date:
January 15, 1998

1996-97 TRUCK ROUGH/NO IDLE AND/OR DTC P0400 STORED IN THE ECM DUE TO EGR VALVE STICKING

APPLIED VEHICLE:
All 1996-97 Truck (D21) 

SERVICE INFORMATION

Use this bulletin if a 1996-97 Truck will not maintain idle or idles roughly after an engine cold soak and/or the MIL is "on" with DTC P0400 stored in the ECM.

A countermeasure EGR valve is available to resolve such incidents if the cause is a sticking EGR valve.

SERVICE PROCEDURE

With the engine cold, perform an inspection of the EGR valve as follows:







1. Apply vacuum to the EGR valve with a hand vacuum pump, then release the vacuum (see Figure 1).

2. Check to see that the EGR valve opens when the vacuum is applied and closes when the vacuum is released.

A. If the EGR valve sticks open or does not open and close smoothly, replace the EGR valve with the countermeasure EGR valve and gasket.

B. If the EGR valve opens and closes smoothly, refer to Trouble Diagnosis in the EC section of the appropriate service manual to diagnose this incident.









PARTS INFORMATION

EGR Valve #14710-86G01
EGR gasket #14719-W7001


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