Several Network Communication DTCs

Joel Diagnostician Soquel, California Posted   Latest   Edited  
Question
Driveability
2008 Lexus RX400h 3.3L (3MZ-FE)
U0001 - High Speed CAN Communication Bus
P0A1D - Hybrid/EV Powertrain Control Module "A"
U0100 - Lost Communication With ECM/PCM "A"
U0129 - Lost Communication With Brake System Control Module "A"
U0131 - Lost Communication With Power Steering Control Module
U0146 - Lost Communication With Gateway "A"
C0205 - ISO/SAE Reserved
U0073 - Control Module Communication Bus "A" Off
U0123 - Lost Communication With Yaw Rate Sensor Module
U0126 - Lost Communication With Steering Angle Sensor Module
Check Engine Light On
No Driveability Concern
B1281 Air Bag Ecu Communication Stop

I need help on this 08 Lexus RX 400 hybrid. I have a lot of data line communication I have the 60 ohms and the 2.5 volts on pin 14 and 6 , I do not have good information of flow chart more than check resistance o wiring.

I do have communication with the scanner to each individual module 

I have some screen shots as well a wave form as I and not expert on network some thing call my attention at the end of data line package there is spike . 

engine dtc: U0001 High speed CAN communication bus state : current 

Hybrid control 9 dtc : P0A1D Hybrid power train control module current 

U0100 lost communication with ecm/pcm 'A'

U0129 lost communication with brake control system control module

U0131 lost communication with power steering control module 

U0146 lost communication with gate way "A"

abs dtc: C0205 front wheel speed sensor LH circuit 

U0073 control module communication bus off

U0123 lost communication with yaw rate sensor module 

U0126 lost communication with steering angle sensor module

B1281 air bag ecu communication stop 

THE FOLLOWING WAVEFORM WAS TAKEN AS VEHICLE CAME IN 

diag​.​net/file/f3uma942y…

I did a hard reset by touching battery terminal , road tested 10 miles in about 6 miles the dtc came back the vehicle does not experience any driveability issues . the next capture was taken after hard reset.

diag​.​net/file/f1lax7igh…

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Phillip Diagnostician
Anchorage, Alaska
Phillip Default
 

Is their another number after the P0A1D code? Like P0A1D 134 or something?

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Stephen Diagnostician
Waterford, Ireland
Stephen Default
 

The P0A1D DTC should have a 3 digit INF code as part of it e.g. P0A1D-144. Regardless of the INF code, DTC P0A1D indicates an internal error within the HV power management ECU, and replacement of this ECU is required if this DTC is reoccurring. The HV power management ECU monitors its own internal operation and will set this DTC and go into a fail safe mode when it detects a malfunction.

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Joel Diagnostician
Soquel, California
Joel Default
 

thank you for your help

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Joel Diagnostician
Soquel, California
Joel Default
 

I did not see it a sib_ code but I am scanning with the launch, I will scan with tech stream now

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Phillip Diagnostician
Anchorage, Alaska
Phillip Default
 

Well looks like you are right, after reading and doing some research they are truly one unit.

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Phillip Diagnostician
Anchorage, Alaska
Phillip Default
 

Question where was the wave forms taken. Which data lines?

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Joel Diagnostician
Soquel, California
Joel Default
 

pin 14 and 6 at DLC connector.

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Phillip Diagnostician
Anchorage, Alaska
Phillip Default
 

Their is also a pin #5 Violet & #13 brown. I'm not sure what those do but they are on a network. SO I would have to somewhat assume they should have some sort of communication wave form. WOuld I be correct that you have checked the voltages and grounds at the HV/ECM ? Forgive me I have not had a network problem on these vehicles before. So even though the chart does say replace this module I…

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Joel Diagnostician
Soquel, California
Joel Default
 

thanks , having all this bunch of dtc I am having issues to organize and where to start as which modules is responsible for dropping the network, clear dtc ,after the second road test got back those dtc except the P0a1d

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Phillip Diagnostician
Anchorage, Alaska
Phillip Default
 

The P0A1D didn't return?

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Joel Diagnostician
Soquel, California
Joel Default
 

Not that one did not return

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Phillip Diagnostician
Anchorage, Alaska
Phillip Default
 

Okay I'm not sure where you are on you diagnostics but what codes have returned so far? You said you could communicate with all modules. And no run ability problems to note?

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Joel Diagnostician
Soquel, California
Joel Default
 

the dc for communication are returning all over , the P0A1D hast not returned. I have that vehicle on the sidefr now

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David Instructor
Kokomo, Indiana
David Default
 

Hi Joel, I agree the approach is to analyze the DTCs and overlap what we know there with schematics. Did not find anything in Alldata for your Lexus (not a power Alldata user so perhaps there are OE schematics there) but did spend a few minutes pouring over the 2 page data line schematics in Mitchell / Shopkey. Here's what I've observed; 1. There are two modules setting communications related…

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Joel Diagnostician
Soquel, California
Joel Default
 

thank you dave , big fan of your training material at AVI

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Phillip Diagnostician
Anchorage, Alaska
Phillip Default
 

David said it better then I could over a forum. And he did it without asking any questions.

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Rassiel Technician
Tampa, Florida
Rassiel Default
   

Looks like you have a module putting out bad data, see the spikes dropping below 1 V on can low and going over 4V on can high? Thats no good, keep the vehicle running while monitoring this network also make sure that this vehicle does not have a diagnostic can if so you can not check at the dlc connector, I say this cause I noticed the dtc U0146 “Lost comm with gateway A”

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Joel Diagnostician
Soquel, California
Joel Default
 

thanks for your advised

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