What chip to inspect for P0505
02-18-2017, 12:29 PM
#1
Senior Member
Thread Starter
Join Date: Oct 2005
Location: Pullman, WA
Posts: 486
What chip to inspect for P0505
Got the code, ordered up a new IACV. Pulled my ECU today to inspect for damage. I was referencing these pics as to what to look for:
http://lh6.ggpht.com/_KN4ZjYRUpiI/S8...2/IMG_1103.JPG
http://lh5.ggpht.com/_KN4ZjYRUpiI/S8...2/IMG_1100.JPG
However, upon opening my ECU I discovered a different layout:
http://i102.photobucket.com/albums/m...psnzilkytu.jpg
I have looked at each of the chips, and cannot see any visible damage, nor smell any burnt electronic smell, but was hoping someone could point out the correct chip to look at before I risk the new IACV. My ECU is from a 2000 GXE 5 speed. On its cover is printed A56-Q14, Z91, GM, and 0302 in addition to Nissan and the manufacturer Unisia JECS Corporation. Thank you for your time.
http://lh6.ggpht.com/_KN4ZjYRUpiI/S8...2/IMG_1103.JPG
http://lh5.ggpht.com/_KN4ZjYRUpiI/S8...2/IMG_1100.JPG
However, upon opening my ECU I discovered a different layout:
http://i102.photobucket.com/albums/m...psnzilkytu.jpg
I have looked at each of the chips, and cannot see any visible damage, nor smell any burnt electronic smell, but was hoping someone could point out the correct chip to look at before I risk the new IACV. My ECU is from a 2000 GXE 5 speed. On its cover is printed A56-Q14, Z91, GM, and 0302 in addition to Nissan and the manufacturer Unisia JECS Corporation. Thank you for your time.
02-18-2017, 09:07 PM
#2
Senior Member
Join Date: Jan 2003
Location: California
Posts: 1,445
You want to inspect the STA508A and/or STA509A chips on your ECU board. They should be in the upper left corner of your ECU board. The chip designation is printed on the chip, and the chip itself is vertically placed.
Last edited by maxiiiboy; 02-18-2017 at 09:10 PM.
02-21-2017, 11:48 AM
#4
Newbie - Just Registered
Join Date: Dec 2016
Location: Stony Brook, NY
Posts: 1
That's an interesting ECU - it definitely has a different layout from mine. There's a daughterboard on yours. But it looks as if the MCU is the same 256 pin QFP, the Hitachi SH-2E.
I have a 2001 SE M/T which threw the P0505 code. In my case, the burned chip was barely even obviously damaged, and there was no smell either. There was a tiny hairline crack all the way around the casing, only really visible under a loupe or a microscope. But there were two clearly blown traces on the top side of the board and the conformal coating had bubbled away and carbonized.
The chip that sometimes burns is a 10-pin SIP. It's soldered into through holes and mounted vertically. I can see three such packages on your photo towards the rear of the left hand side of the board, if you were looking from the header side. They're not in the same places as on my ECM but they look the same. You want to look closely at the traces and check continuity to the pinouts. Pins 1 and 10 are ground - pins 2,4,6,8 are the gates, and pins 3,5,7,9 carry stepper motor current. So the traces running from 3,5,7,9 are the ones that are likely to be damaged.
On mine the chip that burned was a Sanken STA509A. It's an array of four mosfets, one each is used to pull the four half coils on the IACV stepper motor to ground. It's a little hard to see the writing on the chips on your board but it looks like you have at least one STA508A which is almost the same as the STA508A but I think it can handle a little higher current if you look at the datasheet.
I replaced my 509A with a 508A. If you're soldering it yourself don't try to desolder the chip without removing the clear conformal coating - it's some kind of resin - or you'll cause more damage to the board. The coating comes off easily with a little bit of acetone, and then you can desolder the chip cleanly and easily.
I have a 2001 SE M/T which threw the P0505 code. In my case, the burned chip was barely even obviously damaged, and there was no smell either. There was a tiny hairline crack all the way around the casing, only really visible under a loupe or a microscope. But there were two clearly blown traces on the top side of the board and the conformal coating had bubbled away and carbonized.
The chip that sometimes burns is a 10-pin SIP. It's soldered into through holes and mounted vertically. I can see three such packages on your photo towards the rear of the left hand side of the board, if you were looking from the header side. They're not in the same places as on my ECM but they look the same. You want to look closely at the traces and check continuity to the pinouts. Pins 1 and 10 are ground - pins 2,4,6,8 are the gates, and pins 3,5,7,9 carry stepper motor current. So the traces running from 3,5,7,9 are the ones that are likely to be damaged.
On mine the chip that burned was a Sanken STA509A. It's an array of four mosfets, one each is used to pull the four half coils on the IACV stepper motor to ground. It's a little hard to see the writing on the chips on your board but it looks like you have at least one STA508A which is almost the same as the STA508A but I think it can handle a little higher current if you look at the datasheet.
I replaced my 509A with a 508A. If you're soldering it yourself don't try to desolder the chip without removing the clear conformal coating - it's some kind of resin - or you'll cause more damage to the board. The coating comes off easily with a little bit of acetone, and then you can desolder the chip cleanly and easily.