Results 1 to 4 of 4

Thread: 1991 Mustang Codes

  1. #1
    Zoom50
    Join Date
    Dec 2013
    Location
    Tarentum
    Posts
    97

    1991 Mustang Codes

    So my check engine light comes on periodically. I am not concerned about the check engine light (I have classic tags, no emissions), but I want to see if you know if these could be affecting my performance. Any advice is appreciated as well as any specific parts to check...My car is never consistently running great with occasional loping idle. I ran the code scanner and this is what I got back:

    14 - Profile Ignition Pickup Circuit Failure (CM)
    18 - Spark Out (SPOUT) Circuit Open (R), Loss Of Ignition Diagnostic Module Input To PCM/SPOUT Circuit Grounded (CM)
    29 - Insufficient Input From Vehicle Speed Sensor -To 1992 (CM), Insufficient Input From Programmable Speedometer/Odometer Module -From 1993 (CM)
    41 - System Indicates Lean -passenger side(R), No o2 Sensor Switching Detected. always lean -passenger side(CM)
    91 - o2 Sensor Circuit Indicates Lean -driver side(R), No o2 Sensor Switching Detected. always lean -driver side(CM), Shift Solenoid 1 Circuit Failure (O)
    81 - Secondary Air Diverter Circuit Failure (O)
    82 - Secondary Air Bypass Circuit Failure (O)

    I erased my continuous memory and will see what codes remain as some of these may be old from the previous owner. Goodies include 306 crate, headers, GT40P heads, MAF, off road h-pipe, AC delete, valve body, 24lb injectors, E303 cam

  2. #2
    Zoom50
    Join Date
    Dec 2013
    Location
    Tarentum
    Posts
    97
    I forgot to add the codes that came back during my engine on test:

    12 - RPM Not Within Self Test Lower Limit (R), DC Motor Did Not Move (O,CM,R), Idle Speed Control motor or Air Bypass not controlling idle properly -generally idle too low
    21 - Engine Coolant Temperature (ECT) Sensor Out Of Self Test Range. 0.3 to 3.7 volts(O,R)
    41 - System Indicates Lean -passenger side(R), No o2 Sensor Switching Detected. always lean -passenger side(CM)
    91 - o2 Sensor Circuit Indicates Lean -driver side(R), No o2 Sensor Switching Detected. always lean -driver side(CM), Shift Solenoid 1 Circuit Failure (O)



  3. #3
    Senior Member fran's Avatar
    Join Date
    Dec 2009
    Posts
    135
    Needs the codes cleaned out & a new tune. Maybe a couple of sensor's.

  4. #4
    Zoom50
    Join Date
    Dec 2013
    Location
    Tarentum
    Posts
    97
    Quote Originally Posted by fran View Post
    Needs the codes cleaned out & a new tune. Maybe a couple of sensor's.

    I went ahead and replaced both O2 sensors, cleaned out the intake/MAF, cleared the codes, and erased the hard drive. Seems to idle much better ... I will test her out later this afternoon.

Similar Threads

  1. 1991 Ford Mustang 5.0 Coupe
    By Sonic03snake in forum Ford Vehicles
    Replies: 1
    Last Post: 03-31-2010, 11:43 AM
  2. F/s 1991 Mustang Gt
    By jclose11 in forum Ford Vehicles
    Replies: 8
    Last Post: 01-19-2010, 11:47 AM
  3. 1991 mustang gt problem
    By chuck94 in forum Fox-SN95
    Replies: 13
    Last Post: 01-01-2009, 06:52 PM
  4. FS-1991 Mustang LX Vert
    By WickedJester in forum Ford Vehicles
    Replies: 0
    Last Post: 05-23-2008, 01:20 PM

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •