CEL comes on/off while driving - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

Vdubbin32 · 06-22-2018, 07:33 PM

When i drive my car it runs and idles fine but I'm getting a cel that comes on and off when I'm driving. if i give it gas it sometimes comes on and then goes off when i let off the gas and cruise. I replaced ignitor chip, ignition coils, spark plugs, maf, and like i said the car drives normal but i wonder why I'm getting this code 21, thanks

rc1honda · 06-26-2018, 05:27 PM

Could be oil pressure. I know my CEL goes on if the oil pressure is to low.

Might want to check your oil pump.

LoSt180 · 07-09-2018, 06:54 PM

On the S14 SR, if you apply 12V to the ECU "check" pin the CEL will start turning on/off based on the O2 sensor seeing rich or lean.

That was an exercise in frustration when mine started doing that one day. My Wiring Specialties harness wired that pin to the OBD2 port, so I accidentally triggered it when I plugged a scan tool in to that (instead of the Consult port).

06-22-2018, 07:33 PM	#1
Vdubbin32 Join Date: Jul 2017 Location: West Chicago Age: 33 Posts: 7 Trader Rating: (0) Feedback Score: 0 reviews	CEL comes on/off while driving When i drive my car it runs and idles fine but I'm getting a cel that comes on and off when I'm driving. if i give it gas it sometimes comes on and then goes off when i let off the gas and cruise. I replaced ignitor chip, ignition coils, spark plugs, maf, and like i said the car drives normal but i wonder why I'm getting this code 21, thanks

06-26-2018, 05:27 PM	#2
rc1honda Zilvia Junkie Join Date: Aug 2008 Location: Chicago Age: 42 Posts: 433 Trader Rating: (5) Feedback Score: 5 reviews	Could be oil pressure. I know my CEL goes on if the oil pressure is to low. Might want to check your oil pump.

07-09-2018, 06:54 PM	#3
LoSt180 Zilvia FREAK! Join Date: May 2013 Location: MD Posts: 1,049 Trader Rating: (18) Feedback Score: 18 reviews	On the S14 SR, if you apply 12V to the ECU "check" pin the CEL will start turning on/off based on the O2 sensor seeing rich or lean. That was an exercise in frustration when mine started doing that one day. My Wiring Specialties harness wired that pin to the OBD2 port, so I accidentally triggered it when I plugged a scan tool in to that (instead of the Consult port).