I'm.going to hit the salvage yard tomorrow to see if they got any recent trucks. I found a PCM on eBay for $80, just need to get it flashed to my vin# Sent from my LGLS990 using Tapatalk
Alright guys, stepped away from the crank sensor for a minute to see if I can find anything out with this p0155 o2 heater circuit codes. This p0155 code states that there is a short in the circuit, it doesn't mean that the sensor is bad, though it did say it could have an internal issue. But since I'm getting the same code for all 3 sensors, don't really think all 3 are bad especially since bank 2 sensor 1 is new. *Voltage testing I tested for power and ground at the 2 white wires on B1S2, no power across the 2 wires. However, if I test each wire with my meter and put one lead of the meter at ground on the battery, I get batt voltage. If I check both wires to the positive post kf the battery, I get nothing. Kinda odd. This test was done with the ignition on, I even tried it with the truck running. *Continuity Looking at the B2S1 (haven't tested the other sensors yet) Tested both white wires at the o2 sensor, got continuity but no voltage. (Short somewhere????) Tested continuity at the truck side of the plug, I have continuity there as well. Have not tested power at the driver side/pcm yet. I have to figure out which wire is the +side of the circuit. At the PCM all it says is "o2 heater control" no - or + note. I know which wire's supply power just not sure which is which. One of the wires runs to one of the injectors (positive side?) I did check all body grounds today and cleaned them. This could still be a PCM issue if the wires that come from the o2 heater control are not sending the right signal, or a signal at all. Sorry for the long post, just throwing up what I'm thinking.
Alright guys, stepped away from the crank sensor for a minute to see if I can find anything out with this p0155 o2 heater circuit codes. This p0155 code states that there is a short in the circuit, it doesn't mean that the sensor is bad, though it did say it could have an internal issue. But since I'm getting the same code for all 3 sensors, don't really think all 3 are bad especially since bank 2 sensor 1 is new. *Voltage testing I tested for power and ground at the 2 white wires on B1S2, no power across the 2 wires. However, if I test each wire with my meter and put one lead of the meter at ground on the battery, I get batt voltage. If I check both wires to the positive post kf the battery, I get nothing. Kinda odd. This test was done with the ignition on, I even tried it with the truck running. *Continuity Looking at the B2S1 (haven't tested the other sensors yet) Tested both white wires at the o2 sensor, got continuity but no voltage. (Short somewhere????) Tested continuity at the truck side of the plug, I have continuity there as well. Have not tested power at the driver side/pcm yet. I have to figure out which wire is the +side of the circuit. At the PCM all it says is "o2 heater control" no - or + note. I know which wire's supply power just not sure which is which. One of the wires runs to one of the injectors (positive side?) I did check all body grounds today and cleaned them. This could still be a PCM issue if the wires that come from the o2 heater control are not sending the right signal, or a signal at all. Sorry for the long post, just throwing up what I'm thinking.
Seems something is amiss since readings at the wires is all crazy. Now its pointing back to the PCM giving false + - to the sensors but the truck is running but throwing codes.
Every now and then I get a p0171 which is lean code for one side and a DPFE code but they don't always show up. I read about someone having the same p0155 code as me for the heater circuit , truck was also throwing a lean code. Ended being his PCM. I still have some readings to gather from other wires, I pulled the fuse box out if the truck to check the wires on the bottom of it for cuts, everything is good.
Who knows with the monkey mechanics the PO was using before. Good checks on continuity of the wiring and no cuts or deterioration of the insulation will put ya back at faulty PCM I'm betting. Still better to check all this out before just throwing one at it in the begining. But therein lies a problem. What if most of those PCM Have the same trouble? Should have been a TSB or a recall that never made it to the approval stage. Galaxy S4 Cetane Powered Android
I'll double check the tests I've already done to be sure. Hopefully I can find a 96 PCM at the salvage yard. Going to a different one this time. Sent from my LGLS990 using Tapatalk
Ran through my wiring diagram for the o2 circuit. Looks like the Red wire is 12v switched ignition, the other 3 wires for each of the sensors going to the heater control are the ground wires. Haven't had a chance to check it out today, had a birthday party tk attend and I should probably spend some time with my other half lol. Let you know what's up tomorrow!
Alright, dug around for a few hours trying different things. I found this walk through another guy did. Tried to duplicate his testings as best I could, I don't have a break out box though. Tried asking around or one, no one has one. My buddy who teaches auto tech doesn't even have one lol. http://www.askamechanic.info/askamech2/content/view/87/47/ Here's what I found, made a little test light with a spare bulb and socket like the guy in the walk through fkr the hell of it. Hooked it up to the 2 white wires at the o2 sensor plug. (Snipped wires free from o2 sensor, put light in place) light DOES NOT light up with ignition on. Checked wires at light with ignition on, across wires shows continuity but no batt voltage(reason why light won't illuminate). Testing both wires individually to the ground post on battery, my meter shows 12v. Kinda odd. What else is odd, both wires show ground with the ignition off when I test them to the positive post on battery. Went ahead and checked pin 94, which should be ground for B2S1, with PCM connected, it shows power with ignition on and ground with ignition off. Pin 49 should be showing ground with ignition on. The power wire for each O2 sensor heater is Red, all power wires run back to the PCM power relay (Why is this wire showing ground when with ignition off?????) I also checked the wires at the B1S2 which is right at the cat, same thing. Power at both wires when on, grounded when off. If you look at the link I posted, the guy checked resistance between 93 and 94 with he PCM still hooked up, I got a reading of 1.3 ohms. The guy in the link got 2.6 ohms I believe, he called that excessive resistance. Checked the resistance at the pins on the actual PCM, got 1.4 ohms. Checked the resistance of the same pins on the spare PCM I have, got the same reading, hmmmmm. Not really sure what that's telling me haha. Something still doesn't seem right though. I should still show both a power and ground at each O2 sensor. What in the hell is going on???? PCM should ground the circuit when the ignition is turned on. I want to call it a bad PCM.
Would also like to add that for the hell of it, I grabbed a brand new OE replacement sensor, same code came on, cleared it s couple times but kept coming back.
