89 stang spittin codes 15 and 67?
- Thread starter jhysock
- Start date
Code 15 - No Keep Alive Memory power to PCM pin 1 or bad PCM (Memory Test
Failure). The voltage to the Keep Alive Memory (KAM) is missing (wiring problem)
or the KAM is bad. The KAM holds all of the settings that the computer "learns" as
it operates and all the stored error codes that are generated as a result of
something malfunctioning while the engine is running. Use a voltmeter to check
the voltage to the pin 1 on the computer - you should always have 12 volts. No
constant 12 volts = bad wiring. If you do always have the 12 volts, then the KAM is
bad and the computer is faulty.
If the computer has to "relearn" all the optimum settings every time it powers up,
the initial 5-30 minutes of operation may exhibit surges, poor low speed performance,
and rough idle.
Note that some aftermarket chips will cause code 15 to set. Remove the chip,
clear the codes and retest.
Before replacing the computer, remove the battery ground cable for about 20
minutes. This will clear all the codes. Retest after several days of running. If the 15
code is gone, then don't worry about it. If it is still there, then you get to do some
troubleshooting.
Wiring diagrams for the proper model years are next…
See the following website for some help from Tmoss (diagram designer) & Stang&2
Birds (website host) for help on 88-95 wiring Mustang FAQ - Engine Information
Diagram courtesy of Tmoss & Stang&2birds
http://www.veryuseful.com/mustang/tech/engine/images/IgnitionSwitchWiring.gif
http://www.veryuseful.com/mustang/tech/engine/images/fuel-alt-links-ign-ac.gif
http://www.veryuseful.com/mustang/tech/engine/images/88-91_5.0_EEC_Wiring_Diagram.gif
Code 67 - clutch not depressed (5 speed) or car not in neutral or park (auto) or A/C in On position when codes
where dumped. Possible neutral safety switch or wiring problem. This code may prevent you from running the Key On
Engine On tests. You can generally ignore this code, since it has no effect on engine performance.
The computer wants to make sure the A/C is off due to the added load on the engine for the engine running tests. It also
checks to see that the transmission is in Neutral or the clutch depressed (T5, T56, Tremec 3550 & TKO). This prevents
the diagnostics from being run when the car is driven. Key On Engine Running test mode takes the throttle control away
from the driver for several tests. This could prove hazardous if the computer was jumpered into test mode and then driven.
The NSS code 67 can be bypassed for testing. You will need to temporarily ground computer pin 30 to the chassis.
Computer pin 30 uses a Lt blue/yellow wire. Remove the passenger side kick panel and then remove the plastic cover from
the computer wiring connector. Use a safety pin to probe the connector from the rear. Jumper the safety pin to the
ground near the computer.
IF YOU JUMPER THE WIRING TO BYPASS THE NSS, BE SURE TO REMOVE IT PRIOR TO DRIVING THE CAR!!! YOU COULD END UP CRASHING AND BURNING!!!
A search would have uncovered this gem...
See the "Surging Idle Checklist for help with all your idle/stall problems. Everything you need to find and fix idle problems is in there.
The first two posts contain all the updates to the fixes. At last count there were 24 possible causes and fixes for surging idle/stall problems. I continue to update it as more people post fixes or ask questions.
Failure). The voltage to the Keep Alive Memory (KAM) is missing (wiring problem)
or the KAM is bad. The KAM holds all of the settings that the computer "learns" as
it operates and all the stored error codes that are generated as a result of
something malfunctioning while the engine is running. Use a voltmeter to check
the voltage to the pin 1 on the computer - you should always have 12 volts. No
constant 12 volts = bad wiring. If you do always have the 12 volts, then the KAM is
bad and the computer is faulty.
If the computer has to "relearn" all the optimum settings every time it powers up,
the initial 5-30 minutes of operation may exhibit surges, poor low speed performance,
and rough idle.
Note that some aftermarket chips will cause code 15 to set. Remove the chip,
clear the codes and retest.
Before replacing the computer, remove the battery ground cable for about 20
minutes. This will clear all the codes. Retest after several days of running. If the 15
code is gone, then don't worry about it. If it is still there, then you get to do some
troubleshooting.
Wiring diagrams for the proper model years are next…
See the following website for some help from Tmoss (diagram designer) & Stang&2
Birds (website host) for help on 88-95 wiring Mustang FAQ - Engine Information
Diagram courtesy of Tmoss & Stang&2birds
http://www.veryuseful.com/mustang/tech/engine/images/IgnitionSwitchWiring.gif
http://www.veryuseful.com/mustang/tech/engine/images/fuel-alt-links-ign-ac.gif
http://www.veryuseful.com/mustang/tech/engine/images/88-91_5.0_EEC_Wiring_Diagram.gif
Code 67 - clutch not depressed (5 speed) or car not in neutral or park (auto) or A/C in On position when codes
where dumped. Possible neutral safety switch or wiring problem. This code may prevent you from running the Key On
Engine On tests. You can generally ignore this code, since it has no effect on engine performance.
The computer wants to make sure the A/C is off due to the added load on the engine for the engine running tests. It also
checks to see that the transmission is in Neutral or the clutch depressed (T5, T56, Tremec 3550 & TKO). This prevents
the diagnostics from being run when the car is driven. Key On Engine Running test mode takes the throttle control away
from the driver for several tests. This could prove hazardous if the computer was jumpered into test mode and then driven.
The NSS code 67 can be bypassed for testing. You will need to temporarily ground computer pin 30 to the chassis.
Computer pin 30 uses a Lt blue/yellow wire. Remove the passenger side kick panel and then remove the plastic cover from
the computer wiring connector. Use a safety pin to probe the connector from the rear. Jumper the safety pin to the
ground near the computer.
IF YOU JUMPER THE WIRING TO BYPASS THE NSS, BE SURE TO REMOVE IT PRIOR TO DRIVING THE CAR!!! YOU COULD END UP CRASHING AND BURNING!!!
A search would have uncovered this gem...
See the "Surging Idle Checklist for help with all your idle/stall problems. Everything you need to find and fix idle problems is in there.
The first two posts contain all the updates to the fixes. At last count there were 24 possible causes and fixes for surging idle/stall problems. I continue to update it as more people post fixes or ask questions.
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