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code P1670 EF signal not detected?

28K views 6 replies 3 participants last post by  jots512 
#1 ·
this is a new thread, i have a running thread on my diagnostics under the thread, '98 E350 fuel pressure.

performed diagnostics and have come to a step where they are asking me to check feedback frequency, i have a scope so i can perform this only problem is my engine doesn't start, so I am not able to perform test. i either have a bad ecm, or a bad IDM.

does anyone have any ideas?

other tests i can perform? anything?

Thanks in advance.
Joe
 
#2 ·
as I mentioned in the other thread the ef signal is a comunication line between ecm and idm .. the loss of this signal can be caused by a idm not powering up IE lack of battery power to it ign power or ground. a bad idm can also set this code if its not comunicating. and broken ef wires between the ecm and idm can cause this.

at this point you need a wiring diagram so as to check all wiring for idm power and the wires fro the ef line with an ohm meter ect .
 
#3 ·
i have detailed wiring diagrams with me
checked BAT+ at Connector 1157 pin 14DG/LG wire, 11.48v present.
checked for ground at C1157 pin 26 BK/W, ground good.
measured resistance from PCM C154 pin 48 GY/W to IDM C1157 pin 4, 0 ohms.
measured resistance between PCM C154 pin 48 and common ground wires pins 51,76,77,& 103. infinitity found.
measured resistance between pcm C154 pin 48 and common 12V wires pins 55,71,&97. 0 ohms measured on each wire with key on engine off, indicating a short to power on the EF feedback signal wire. I proceded down the circuit to the large square connector above center of engine held together with 10mm head bolt. disconnected connector with DVOM still connected and meter read infinity, indicating fused wires in harness leading to engine.

well, i reconnected large connector, and meter reads infinty. indicating no short. this is where i am stumped in my diagnosis. short of ripping the harness out to peel away sheathing, i find no short. telling me i my have a faulty pcm. harness costs as much as pcm.


What to do... what to do.... what to buy...?

sorry for long post, i thought if i read what i had done, i could see if ihad gone wrong somewhere in diagnosis.

thanks for any suggestions.

joe
 
#4 ·
Somebody has a pcm for sale for 150 bucks in the FOR SALE section. I don't know if it is the right code or if it matters but worth a shot over the dealers price.
 
#5 ·
if he needs anything it will be the wiring or the idm in my opinion there are only 2 idms the black new style and the silver old style.

now that the wire now tests ok do you still get the ef fault code?? if not you may have more issues if it still wont start also I would clean all connections well and coat with dialectric grease

this kind of thing is hard to help with in forums so sorry for the lack of answers
 
#7 ·
ok, I got her running. I went to inspect IPR connector and ICP connector and found the connector for IPR bad. The rubber insulation that lives on male connector was oil soaked and deteriorated, as well as the insulators for each wire, contact was being made right at the connector. I removed fuel filter housing and replaced the harness connected to it, started cranking, after a few minutes, she fired off, ran a little crappy then cleared up. went on drive for about 20 miles, she seems alright.

I do thank everyone for their help, If i can assist anyone i will.

Thanks
Joe
Austin,TX
 
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