Go Back   Infamous Nissan - Hardbody / Frontier Forums > Tech Area > Wiring and Electrical

Reply
 
Thread Tools Display Modes
Old 02-22-2017, 10:47 PM   #1
pressley_p
 
Join Date: Feb 2017
Location: Tennessee
Posts: 1
Vehicle: 1994 Nissan
Thanks: 0
Thanked 0 Times in 0 Posts
Default ECU problems with MAF?

I've got a 94 hard body 4x4 with ka2.4. I've replaced the MAF twice b/c it was throwing a 12 code. I've got new injectors,plugs,dizzy cap, rotor button, Ambient air temp sensor in the air box, re-soldered the wires under the hood, timing is correct, and I've narrowed it down to the ECU is not sending a signal to the AMF. I'm checking it straight from the ECU with the vehicle running and it's only showing .o6 on my meter, regardless of me pushing the pedal to see if it changes. Has anyone else seen this problem before? And yes it's stuck in limp mode.
pressley_p is offline   Reply With Quote
Old 02-24-2017, 11:43 AM   #2
RONNIEBOY
 
Join Date: Jul 2014
Location: Sunshine State!
Posts: 1,381
Vehicle: 2003 Nissan pathfinder SE and 2000 ML320 .
Thanks: 87
Thanked 160 Times in 150 Posts
Default

Welcome to infamous Nissan
RONNIEBOY is offline   Reply With Quote
Old 02-24-2017, 12:04 PM   #3
jp2code
Software Developer
 
jp2code's Avatar
 
Join Date: Dec 2011
Location: Longview, TX [USA]
Age: 49
Posts: 8,872
Vehicle: 94 LB 2x4 Manual VG33e
Thanks: 1,285
Thanked 1,104 Times in 974 Posts
Default

Most likely a cut in the wiring.

The engine harness is usually tucked away pretty good, so that is rarely the problem.

Look at the wiring around the MAF. Look for corrosion on the connectors, breaks in the shielding, or any exposed wires.
__________________
Joe (not a mechanic!) Don't have an account? EMAIL ME
Factory Service Manuals: https://www.nicoclub.com/FSM/Hardbody/
Walk-through: Checking Nissan Trouble Codes
1994 VG30E to VG33E with H256 Cams

jp2code is offline   Reply With Quote
Old 02-25-2017, 02:45 AM   #4
cadillacdude1975
The Gear Jammer
 
cadillacdude1975's Avatar
 
Join Date: Apr 2013
Location: Chattanooga, TN
Age: 46
Posts: 8,800
Vehicle: 87 D21 SE KC V6 2wd 5sp & 86.5 V6 SE auto
Thanks: 317
Thanked 975 Times in 902 Posts
Default

corrosion was my problem. i cleaned the terminals up and all has been good for almost 4 years now.
__________________
"Im officially lost" - wildbill
cadillacdude1975 is offline   Reply With Quote
Old 05-28-2018, 10:44 AM   #5
wen2008
 
Join Date: May 2018
Location: GU
Posts: 19
Vehicle: 93 D21
Thanks: 5
Thanked 1 Time in 1 Post
Default

reground ur maf. i had same issue. power source to maf was good but when i plug in maf and back probe the power and ground to maf i was only getting 3-5 volts regrounded maf straight to anywhere on cab and got full 12 to maf and ran good
wen2008 is offline   Reply With Quote
Thanked by:
jp2code (05-28-2018)
Old 05-28-2018, 10:45 AM   #6
wen2008
 
Join Date: May 2018
Location: GU
Posts: 19
Vehicle: 93 D21
Thanks: 5
Thanked 1 Time in 1 Post
Default

a wiring diagram also helps alot check continuity between the 3 maf wires to ecu
wen2008 is offline   Reply With Quote
Old 05-31-2018, 04:01 PM   #7
Alexg89
 
Alexg89's Avatar
 
Join Date: Jun 2015
Location: Cocoa
Posts: 140
Vehicle: 1995 hardbody ext cab ka 2wd 1998 Frontier ext ka 4wd 2007 D40 CC 4wd w/2in leveling kit
Thanks: 35
Thanked 15 Times in 13 Posts
Default

Quote:
Originally Posted by wen2008 View Post
reground ur maf. i had same issue. power source to maf was good but when i plug in maf and back probe the power and ground to maf i was only getting 3-5 volts regrounded maf straight to anywhere on cab and got full 12 to maf and ran good

Reground maf? 12volts? im looking in my EC section of the FSM and cant find a voltage for it but i thought it was only 5 votls.. or am i thinking TPS

and by reground your just putting a jumper from on e of the 3 bolts to the cab correct?
__________________
Daily - 2007 Nissan frontier crew can 4wd , first truck/project - 1995 King can 2wd , mud truck - 1998 frontier ext can 4wd owned: 1991 single can 2wd, 1994 ext can 2wd, 1985 720 4wd, 2000 crew can 2wd v6
Alexg89 is offline   Reply With Quote
Old 05-31-2018, 04:42 PM   #8
jp2code
Software Developer
 
jp2code's Avatar
 
Join Date: Dec 2011
Location: Longview, TX [USA]
Age: 49
Posts: 8,872
Vehicle: 94 LB 2x4 Manual VG33e
Thanks: 1,285
Thanked 1,104 Times in 974 Posts
Default

Use this link to get the EC.pdf of the Service Manual:

https://app.box.com/s/k8zz8kqigim4qe52rci9dmlgw1gt786s

Diagnostic for Code 12 starts on EF & EC-228. The wiring diagram shows the WHITE fusible link (info here: FUSIBLE LINKS), the ECCS Relay, and the Engine Ground.

Page 229 shows you want battery voltage between Terminal C and ground. With the ignition turned OFF, you should have continuity between Terminal B and Pin 17 of the ECM, and continuity between Terminal A and Pin 15 of the ECM.

If you need to check your MAF component, that is on page EF & EC-280, but all that page shows is to check the hot wire air passage for dust. If it has dust in there, only clean it out with MAF cleaner!
__________________
Joe (not a mechanic!) Don't have an account? EMAIL ME
Factory Service Manuals: https://www.nicoclub.com/FSM/Hardbody/
Walk-through: Checking Nissan Trouble Codes
1994 VG30E to VG33E with H256 Cams

jp2code is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT. The time now is 08:23 AM.


Powered by vBulletin® Version 3.8.6
Copyright ©2000 - 2018, Jelsoft Enterprises Ltd.