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DTC P035


dibobberg

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My 1994 Eldorado is displaying DTC P035 : " Reference low voltage is out of range."

I have no service manual. (I have a service manual for my 97 Eldorado) I would appreciate a clue as to what this code is about or a cross-reference to a similar code in my 97 manual.

Car is surging and stumbling. I can follow the diagnostic information in my 97 manual for this kind of problem, but first I want to check out P035. I would like to know if a 94 manual will be helpful on this particular code.

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P034 (E034) ......................................... MAP Sensor Signal Out of Range

P035 (E035) .......................... PCM reference low signal voltage Out of Range

P036 (E036) ................................. EGR Valve Pintle Position Out of Range

P037 (E037) .............................................. Shorted MAT Sensor Signal

P038 (E038) ................................................. Open MAT Sensor Signal

P035 is in a group of codes that reference sensor values out of range. I don't know what the PCM reference voltage is in OBD I but it is probably an internally generated voltage that is used to drive sensors, or to set thresholds for decisions from sensor outputs, it would mean that there is likely a bad connection between the PCM and the battery, the battery ground, or a ground close to the PCM. I'm thinking battery cable where it bolts to the positive terminal of the battery, but I would look at all of the connections and grounds to the PCM, and the battery ground. When you find it, the surge and miss might be taken care of too.

CTS-V_LateralGs_6-2018_tiny.jpg
-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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dibob,

PO35 on your 94 Eldo is Ignition Ground Voltage Out of Range.

Is it intermittent? The service manual states that if it is intermittent then it could be due to an improperly installed PCM. "This may cause the PCM to not be electrically isolated from the body ground."

If you need more info I'll snap a pic of the pages for you.

"Burns" rubber

" I've never considered myself to be all that conservative, but it seems the more liberal some people get the more conservative I become. "

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Thanks to you both. I'll take a look at the PCM connections. Nothing has been apart recently, except the battery ground. I shoehorned a starter in a week or so ago. The P035 is a current, not history, code and it reappears immediately after it is cleared. So I'll look for something broken or corroded. Thanks again.

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If the P035 is current, you can look for voltage on a "ground" connector with a voltmeter. If you don't have one, you can get one for about $15 or so in a bubble pack from Radio Shack, K-Mart, Target, Wal-Mart, or an auto parts store.

Since you just changed the starter and modified your battery ground cable, those are the first two things to check. Look for is a voltage at the negative terminal of the battery relative to the frame or chassis, then from the chassis to the engine. The next thing to check is the ground on the PCM relative to the engine. If anything measurable shows up, you can go right to the ground connection and fix it.

CTS-V_LateralGs_6-2018_tiny.jpg
-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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