Injector poll signals to cyl. #1 and #4

KBARROWS122

MEMBER
2001 TOYOTA TACOMA
156,000 MILES

I have replaced plugs, coil to 1 and 4 cyl. Its a 3.4 liter engine. Previously codes were coming up for o2 sensors which were also replaced along with engine temp. Sensor and thermostat!Now my trk has been in garage for 5 days and they determined that I have spark but no signal is getting sent for #1 and #4 injector polls. Any idea what the problem is? Where does this signal come from? Its either a bad wire or the computer itself? Please respond asap as I dont have a vehicle right now.

1 Reply

MADMIKE1735

MECHANIC
951 POSTS

Well your signal ultimately comes from your pcm. Thats where your injector driver is. However, your pcm gets signals from other sensors, and thats how it recognizes what pulse to send to the injectors. What was the start of this problem? You had codes for your 02 sensors. Is that what it went to the shop for? How do they know if you have signal to the injectors? Did they check with a noid light? Verify pulse? To me personally, the amount of stuff replaced seems like they are chasing something. Can I get a little more info if you have any?