Pulled Code P1676 & P0420
 

Hey guys,

I got these codes pulled @ Autozone today. I'm don't know much about cars, so I was hoping you all could give me advice on what I should do next?

Thanks all!

DTC P0420: CATALYST SYSTEM - EFFICIENCY BELOW THRESHOLD
NOTE: Trouble shoot DTC P0137, P0138 or P0141, if set, before
proceeding.
1) Perform PCM reset procedure. See PCM RESET
PROCEDURE/CLEARING CODES under SELF-DIAGNOSTIC SYSTEM. Start engine
and run at 3000 RPM, with no load and transmission in Park or Neutral,
until radiator fan comes on.
2) Connect scan tool to vehicle. Test drive vehicle at 40-55
MPH for at least 2 minutes. Decelerate with throttle completely closed
for at least 3 seconds. Reduce speed to 35 MPH and try to hold until
scan tool indicates FAIL or PASS as TWC test result. If test result
fails, check TWC and repair as necessary. If test result does not
fail, problem is intermittent. System is okay at this time.


DTC P1676: FRAME-TO-POWERTRAIN TORQUE DOWN REQUEST (FPTDR)
SIGNAL LINE FAILURE
1) Perform PCM reset procedure. See PCM RESET
PROCEDURE/CLEARING CODES under SELF-DIAGNOSTIC SYSTEM. If DTC P1676 is
set, go to next step. If DTC P1676 is not set, problem is
intermittent. System is okay at this time.
2) Turn ignition off. Disconnect PCM 12-pin connector and
ABS/TCS control unit 16-pin connector. ABS/TCS control unit is located
to right of battery. Measure continuity between ground and PCM 12-pin
connector terminal No. 1 (Pink wire). If continuity is not present, go
to next step. If continuity is present, repair short circuit in wiring
between ABS/TCS control unit and PCM.
3) Measure continuity of Pink wire between ABS/TCS control
unit 16-pin connector terminal No. 1 and PCM 12-pin connector terminal
No. 1. If continuity is present, go to next step. If continuity is not
present, repair open circuit in Pink wire.
4) Reconnect PCM 12-pin connector. Connect jumper wire
between PCM 12-pin connector terminal No. 1 (Pink wire) and PCM 31-pin
connector terminal No. 28 (Yellow/Blue wire). Perform PCM reset
procedure. See PCM RESET PROCEDURE/CLEARING CODES under SELFDIAGNOSTIC
SYSTEM. Start engine and wait 60 seconds. If DTC P1678
sets, replace ABS/TCS control unit. If DTC P1678 does not set, replace
PCM.

PCM RESET PROCEDURE/CLEARING CODES
NOTE: Before disconnecting battery or removing fuse, obtain anti
-theft code for radio. After battery is reconnected, CODE will
appear on radio display. Enter 5-digit code to restore radio
operation. If code is entered wrong 3 times, leave radio on
at least one hour, then enter code correctly. Any time radio
power is lost, pre-selected radio stations will have to be
set. For more information, see owner’s manual.
Without Scan Tool
To clear PCM memory without using a scan tool, remove CLOCK
BACKUP fuse No. 13 (7.5-amp) from underhood fuse/relay box for 10
seconds.
Using OBD-II Scan Tool
Clear codes with OBD-II scan tool. Connect and operate scan
tool in accordance with manufacturer’s instructions.

Thanks Optomos!

I called the dealer...they said they wont' trust the codes that I gave them. They want $94 to pull the codes and I can put that $94 towards the charge to fix this. IS this normal for a dealer to do? This is my first car, so I'm not familiar with what the behavior of service guys is.

Also..Do you guys think this is something i coudl fix myself or definately have to go to the dealer?

'99 3.2 TL

they wont trust the codes?? wtf tell them to fuck off.

Haha!!! Yeah, I guess I should do that...this is the Valley Stream Acura Service Center in New York(Long Island) for your reference guys... I'll try some other dealers a bit away and see waht they say...

just wondering-- what did happen with this case with your P0420 throttle code? the guy did the test to check and it passed-- so based on what was written here they said it was intermittent--

After two years-- just wondering was there any failure in the cat or did you need to have the dealer replace the cat?

any help is most appreciated.

And what happenned to the p1676 code...I'm havin' the same issue

yea i got that p1676 code to

Did you guys follow the test procedure?

Pcm = ecu?

Yes

And where is our ecu located...99 tl non navi here...thanks in advance

in front of the center console on the floor. you will have to remove the side panels for easier access.

2) Turn ignition off. Disconnect PCM 12-pin connector and
ABS/TCS control unit 16-pin connector. ABS/TCS control unit is located
to right of battery.

To the right of my battery all I see is the air filter housing...any help would be appreciated...thanks

Our ABS/TCS plug is on the right side of car, opposite of battery.

I also have only code P1676. I followed the above testing procedure.

For step #2, I got a result of 11k Ohm with polarity one way, and infinite resistance with polarity the other way. I see no reason for this difference unless there is a diode in the cable, which seems strange to me. But I took the 11k Ohm as my result. I also wiggled the harness to see if I could change the result and could not. Since I do not know if this is considered a result of continuity or no continuity, I decided to go to step #3.

For step #3, I got a result of 22k Ohm. Since I do not know if this is considered a result of continuity or no continuity, I decided to stop. Main point is that I am hopeful that I do not need to replace the ABS/TCS unit or the PCM; therefore I did not even want to perform step #4 yet!

Regarding step #4, I am not sure whether or not to keep the jumper connected while performing the PCM reset and while starting/running the engine. The alternative would be to connect the jumper and then immediately remove it before proceeding with the PCM reset and engine starting.

Any conclusion about my final diagnosis from the above results? Any clarification regarding procedure of step #4?

Thx!!

lewis3000us

I resolved this issue and reported on it here: link.

So besides the ignition switch ( I have a 2000) what has everyone else found out/fixed with this code? are you finding you have to replace the pcm and or is it just a short?

Thanks!