P0113 IAT Sensor Code Repair
11-21-2009, 11:06 AM
#1
Drifting
Thread Starter
P0113 IAT Sensor Code Repair
My 97 2.5 TL threw a P0113 intermittently some time ago. It went away while another problem (oil in distributor) was causing no start/missing issues.
P0113 returned recently and would immediately reappear after resetting ECM. P0113 is open in the Intake Air Temperature (IAT) sensor, wiring, or ECM fault.
Diagnostics checks for open IAT sensor by shorting the harness connector pins and checking for output temp change on OBD2 monitor which I have. This showed no change indicating the mass air flow/IAT sensor module was not the problem.
This left wiring or connector fault or bad ECU, none of which seemed promising. I checked wiring by establishing a ground from pin on connector at underhood sensor end and checking for ground at the connector to the ECM end. Both wires showed good continuity, leaving bad ECM. I was actually relieved at this result as finding a wiring fault in the harness was not an appealing project.
I've never had a bad ECM, but removed the unit and opened the box to see if anything was obvious. I traced the IAT input lead (D8) from connector onto circuit board and immediately noticed a dark spot about size of dime near two electrolytic capacitors. I cleaned up w/ alcohol and found what looked like a break in the IAT input lead. I think the damage came from a corrosive product from a leaking capacitor. This board proved too fine to repair, even w/ magnifying glasses. Board is incredibly fine w/ leads about size of coarse hair and tiny surface mount resistors everywhere.
I decided to order a replacement used unit. I found one through car-part.com for $45 including shipping. Prices ranged from $45-$350. I called the salvage yard and received the ECM in about a week. It looked fine, but I did not open the box to examine the circuit board as the box was sealed (30 day warranty). I installed ECM and everything seems fine so far.
So ECM's do occasionally fail. My first one on a Honda or Acura product.
Regards
P0113 returned recently and would immediately reappear after resetting ECM. P0113 is open in the Intake Air Temperature (IAT) sensor, wiring, or ECM fault.
Diagnostics checks for open IAT sensor by shorting the harness connector pins and checking for output temp change on OBD2 monitor which I have. This showed no change indicating the mass air flow/IAT sensor module was not the problem.
This left wiring or connector fault or bad ECU, none of which seemed promising. I checked wiring by establishing a ground from pin on connector at underhood sensor end and checking for ground at the connector to the ECM end. Both wires showed good continuity, leaving bad ECM. I was actually relieved at this result as finding a wiring fault in the harness was not an appealing project.
I've never had a bad ECM, but removed the unit and opened the box to see if anything was obvious. I traced the IAT input lead (D8) from connector onto circuit board and immediately noticed a dark spot about size of dime near two electrolytic capacitors. I cleaned up w/ alcohol and found what looked like a break in the IAT input lead. I think the damage came from a corrosive product from a leaking capacitor. This board proved too fine to repair, even w/ magnifying glasses. Board is incredibly fine w/ leads about size of coarse hair and tiny surface mount resistors everywhere.
I decided to order a replacement used unit. I found one through car-part.com for $45 including shipping. Prices ranged from $45-$350. I called the salvage yard and received the ECM in about a week. It looked fine, but I did not open the box to examine the circuit board as the box was sealed (30 day warranty). I installed ECM and everything seems fine so far.
So ECM's do occasionally fail. My first one on a Honda or Acura product.
Regards
Thread
Thread Starter
Forum
Replies
Last Post
Jamus22
2G TL Problems & Fixes
24
06-11-2023 10:08 AM
dirleton
2G RDX (2013-2018)
8
09-28-2015 04:48 PM
