EEC-IV self test procedure article Copyright 1993 Scott Griffith- All rights reserved. This article was originally written by me for the Northern California Shelby Club newsletter, and run in a slightly edited form on the Mustangs Mailing list. ------------------------------------- Late Model Corner- the EEC-IV Self Tests The smallblock Ford has come a long way in the last 30 years. In the simple "good old" days, the hot setup was a sizable Holley and a hot cam, and carburetion was set up with an eye on the plugs, an ear tuned for detonation, and a nose near the tailpipe. Many of us have whiled away a lot of pleasant hours this way over the years. And now we have come to a time when there is a bleeding computer in there! A computer that claims to understand how a motor is supposed to work, and that hides all the fun stuff from us. For those of us with late models, it seems like the fun is gone forever. Well, not really. This computer is what makes it possible to hang a Paxton on our cars with very little more than a couple of wrenches and a drill, and to set it up for good power without investing a set or two of melted-down pistons in the effort. It makes the thrash of rejetting the night before an event, in an effort to get the thing to run clean now that the new headers are installed, a thing of the past. And surprisingly, it makes the process of maintaining and troubleshooting all that federally-mandated pollution plumbing a relatively easy project. It turns out that the damned thing is our friend after all, especially once a few simple tricks are learned. Since I am well known as a hopeless computer weenie, and there's no way I'll ever be able to beat that rap, that's what this article is about. I was corresponding with a friend the other day, and he asked a good question. "I understand that the engine computer of the Mustang can be accessed, and that error codes can be obtained and looked up in the Ford manuals, but how are the codes accessed? Do you need some kind of computer? Is it difficult? I'm not really interested in tuning my engine right now, just in the error codes." Nope, it's not high-tech at all. You just need a piece of wire, and maybe a voltmeter if your car has no Check Engine light, and you can run the EEC-IV Quick Tests in the privacy of your own garage. These can give you an amazing wealth of information on the machine's health, without getting your knuckles dirty, and without pulling one plug or reaching for the leakdown tester. There are two tests you can do- the Key-On, Engine Off test (KOEO), and the Key-On, Engine Running (KOER).The two tests tell you different things, and each has its place. In order to run either test, the car has to be fully warmed up to operating temperature, and the car must be in neutral (both these steps are critical, or the only codes you will get will be the codes for "coolant too cold" and "transmission not in neutral"! Also make sure that the heater and A/C are off, or you'll get the code for "AC is on", which is the same as the code for "tranny not in neutral"... To run the tests, you must locate the EEC-IV test connectors. In the late model Mustang, these are in the engine compartment, right in front of the driver's side hood hinge. There are two connectors of interest- one is a 6-pin connector, and the other is a single pin connector. Both use 1/4" quick disconnect-style terminals, so you'll probably want to make yourself a jumper about 8" long with a 1/4" male QD terminal on each end, if you mean to do this often. Otherwise, any random chunk of wire will do. Here's the pinout for the EEC-IV connector, looking at it from the working side (looking into the female terminals). Note that only these three pins may actually have terminals in them- the other positions may be empty: Signal Return | V _________________ / ___ ___ \ / \ | ___ ___ ___ ___ | |___________________| ^ ^ | | STO FP test The left pin in the center group of 4 pins is the Self Test Output pin (STO). The single terminal hanging loose is the Self Test Input pin (STI). To run the test, you must either have a Check Engine light, or hook up an analog voltmeter. If you have the Check Engine light ('87 and later cars), just watch it during the tests- it will flash the codes. Otherwise, hook up your voltmeter between the positive terminal of the battery, and the STO pin above- you'll count its needle sweeps to get the codes. The FP test pin, when grounded, runs the fuel pump continuously- but that's just FYI. You won't deal with that pin for these tests. To enable the KOEO test, connect your wire jumper between the STI pin (dangling off by itself) and the Signal Return pin above. Then, turn the ignition on, but don't crank the starter- the EEC-IV will enter the KOEO test. During this test, 5 things will happen. First, you'll hear a bunch of clicking for a few seconds as the EEC-IV exercises its valves and actuators, and takes readings from its sensors. Second, if you're using a voltmeter, you'll see a series of very fast pulses go by- they may register a volt or two. These are the "fast codes" that the real STAR scan testers use, but they go by too fast (100x the normal scan rate) to be of any use to us. If you're watching the CE (Check Engine) light, you won't see anything. Third, you'll get the on-demand codes- these indicate what the EEC box has found problems with _at the moment of the test_. They will be presented to you as either flashes of the CE light, or sweeps of the needle on the voltmeter. The code 21 would be presented as flash-flash, pause, flash. The on-demand codes will be presented twice- if the EEC-IV has found nothing wrong, it will give you code 11, twice: flash, pause, flash, longer pause, flash, pause, flash. The flashes and pauses for a given digit are each 1/2 second. The longer pause between digits are 4 seconds. The longer still pauses between codes are 6-9 seconds. If you'd like to see a code just to see what they look like, leave the trans in gear (MT) or drive (AT), or push in the clutch- and you'll get code 67 repeated twice. If there is more than one code detected, they will be presented in sequence, twice: 22, 47, 22, 47. Fourth, you'll get the separator code. The Ford manuals call this code 10, but you can't see the _absence_ of a pulse for the 0- you'll just see a 6-to-9 second pause after the last "on-demand" code, then a single flash. Fifth, you'll get the "continuous" codes- these are the codes that the EEC-IV has stored in its non-volatile memory from events that have occurred while you were driving in the past. Another 6-to-9 second pause after the separator code, and you'll get another sequence of 2-digit codes that will look exactly like the on-demand codes. If all is well, you'll once again see 11,11. So for example- if at some point in the past your throttle position sensor has wigged out while driving, you'll get a 23 in the continuous codes. If it's still wigged out at the time you start the test, you'll see it as a 23 in both the on-demand and continuous codes. One last item is how to clear the continuous codes, so that you can see if new ones crop up. This is simply done by disconnecting and then reconnecting your jumper after all the tests have been run and the codes have been received. Pretty simple, _very_ powerful. Unquestionably your friend. Perhaps there's something to this computer stuff, after all. To do the KOER test, set the car up as above. Then with the STI/signal return jumper disconnected, start up and run it at 2000 RPM or so for two minutes, to thoroughly warm up the EGO sensors and get everything stable. Shut down, reconnect the jumper, and immediately restart, and the EEC-IV will go into the KOER test. Several things will happen. The first is that you'll get the engine ID code- 2 pulses for a 4-cylinder, 3 pulses for a 6, and 4 for a V8. Then the EEC-IV will begin playing with its actuators and sensors, trying to fool them into going to the extremes of their ranges. During this interval the car will run very poorly at times- it may go rich, lean, stumble, buck, and do all manner of unpleasant things. This will last from 6 to 20 seconds. After this interval, the motor will smooth out and begin an even idle. You will then see a single flash or sweep of the needle. This is the Dynamic Response code, which is your cue. After this code, you have 10 seconds to snap the throttle wide open, just long enough to get above 2000 RPM. Once the engine gets above 2000 RPM (it won't take long at WOT with no load!), release the throttle, and let the engine go back to idle. This part is lovingly called the "goose test". The EEC-IV needs to see what happens at high throttle settings to make sure all of its sensors and actuators work properly, so you get to help out by goosing it. This test will last from 4-15 seconds. The goose test is followed by fast codes (which only those of us stuck with a meter will be able to see, and we can't do anything with them), followed by the KOER on-demand codes exactly as above. If all was well, you'll get 11-11. If you didn't goose it enough, you'll get a 77 and get to do it over again. At this point you can optionally run the SEFI or Cylinder Balance test. If you have an '87 or later, lightly tap the throttle (it only takes a small movement) WOT), and release it. Owners of '86s will have to go WOT briefly. After a little while, the EEC-IV will begin cutting the injector to each cylinder in turn, and looking for a drop in RPM. If there is no drop associated with any individual cylinder, then there is some problem there (that may or may not be related to the injection system- you could have a valve problem, or a fouled plug, or a shop towel stuck in the intake runner, and get the same effect). This test takes about 90 seconds. If a cylinder is found by this test to be weak, a single-digit code will be flashed telling you which one (1-8). If all is well, the code will be 9. If it gives you a 77, it got confused (perhaps you bumped the throttle) and you need to start over and rerun the test. '87 and later cars can then rerun the SEFI test after it finished, again by just tickling the throttle (saves having to go back through the whole KOER test). It also relaxes the criteria for "fail" with each retest, so if one cylinder fails the first time but passes the second, it's only a little weak- whereas if it fails 3 times in a row, it's profoundly dead. Those of us with '86s have to go back to Square 1 to rerun, and we don't get this progression of thresholds to help us troubleshoot. There's much more to it than this. But that gets way beyond the scope of one month's article. This is the procedure, to get you started. Next month's article will document the codes and their meanings. But if you're really interested in this stuff, this is where the Ford factory "Engine and Emissions Diagnosis Manual" (the H manual), and/or the Probst book "How to Understand, Service, and Modify Ford Fuel Injection and Electronic Engine Control" come in. The Ford factory shop manuals are available from Helm, Inc., (313) 865 5000. The Probst book is $29.95, from Robert Bentley, Cambridge, MA, ISBN 0-8376-0301-3. Phone number is (800)423-4595. On the other hand, if you just get 11's, then fill the tank and go out for a flog with my blessings. That's the most likely outcome- luckily for us enthusiasts, one thing that Ford hasn't changed in the last 30 years is that the smallblock motor is one of the most reliable machines in the history of Man. And nobody need ever know that you've given in and become a part time computer weenie, too. Happy testing! *********************************************************************************** EEC-IV error codes article Copyright 1994 Scott Griffith- all rights reserved This article was originally written by me for the Nothern California Shelby Club newsletter, and run in a slightly edited form on the Mustangs Mailing list. ------------------------------------- Late Model Corner- the EEC-IV Self Test Error Codes Well, it's time to grab the bull by the tail and look at the situation headon. I'm going to try and paraphrase the EEC-IV selftest code dictionary, and get it online here. Now, note that the codes mean different things depending upon what model car you have- I'm going to do a very Mustang-specific thing and list only the meanings for 5.0L SEFI and SVO 2.3L Turbo applications. So you guys lurking here with the Escorts, pickup trucks, and SHOs may not find these definitions to your liking. Also, these codes are assembled from several different sources, but the primary reference has been the Ford service self-test code summary slide charts for '86-93 cars. So this rev 1.2 list may be subject to some change! My thanks to Dan Malek for his kind research into the codes for the 2.3L Turbo motors for the SVO. In these definitions, the EEC-IV is referred to by its new OBD-II mandated nomenclature as the PCM (Powertrain Control Module). The vendor-independent OBD-II nomenclature is slowly pushing all of the old Ford-specific names for sensors and everything else off of the edge of the world, so this update now uses _both_ forms. In parenthesis after the code itself will be flags for the tests during which it may occur: "o" for KOEO, "r" for KOER, and "c" for continuous or memory codes. Codes flagged with an asterisk will cause the MIL (Malfunction Indicator Light, better known as the Check Engine light) to come on. EEC-IV Diagnostic Codes, Rev. 1.2 12/27/94 11 (orc): No problems found in this portion of the test 12 (r): PCM could not increase idle speed above normal idle during KOER high RPM idle check. Suspect throttle body coking. 13 (r): PCM could not lower idle speed below normal idle during KOER low rpm idle check. Suspect Idle Bypass valve problems. 14 (c): Intermittent PIP signal operation. Suspect PIP sensor or TFI module, or grounding or interference problems at the TFI module. 15 (o): PCM ROM test failure- failure is internal to PCM. (c) PCM KAM (Keep Alive RAM Memory) failure. 16 (r): 2.3 Turbo. ISC can't keep engine from stalling. Check for short to ground in ISC circuit. 17 (r): 2.3 Turbo. Can't maintain curb idle speed. Check for incorrect idle adjustment, faulty throttle body, intake air leaks. 18 (rc): Loss of TACH signal from TFI (Thick Film Integration- the module on the side of the distributor) module to the PCM. There is an open in the SPOUT circuit. Suspect SPOUT connector. 19 (o): Failure of PCM voltage regulator. Replace PCM. 21 (or): ECT (Engine Coolant Temp) out of range. Coolant is less than 50degF for KOEO, or less than 180degF for KOER, or greater than 250degF for either. If coolant temp is in proper range, suspect ECT sensor. (It won't be, for KOER tests on cars that have a 160degF thermostat!) 22 (orc*): MAP (Manifold Absolute Pressure, for speed-density cars) or BP (Barometric Pressure, for mass-air cars) sensor signal out of range. Suspect MAP or BP sensor and harness. 23 (or): Closed throttle TP (Throttle Position) sensor voltage out of range. Suspect TP sensor. 24 (or): ACT (Air Charge Temperature)/IAT (Intake Air Temperature) sensor voltage out of range. Suspect ACT sensor and harness. 1984-85 2.3 Turbo - Vane Air Flow voltage out of range. 25 (r): 2.3 Turbo. Knock Sensor failure, knock not sensed during dynamic response test. 26 (or): VAF (Vane Air Flow, 2.3L Turbo) or MAF (Mass Air Flow) signal out of range. Suspect sensor and harness. 27 (r): VSS (Vehicle Speed Sensor) voltage too low, servo leaking down, IVSC (Integrated Vehicle Speed Control) test. 28 (r): Servo leaking up, IVSC (Integrated Vehicle Speed Control) test. 28 (or): 1986+ 2.3 Turbo. Vane Air Temperature out of range. 29 (c): VSS (Vehicle Speed Sensor) voltage too low. 31 (orc*): EVP (EGR Valve Position) or PFE (Pressure Feedback EGR) sensor voltage too low, or EVR (EGR Vacuum Regulator) circuit problems. 32 (orc): EVP or PFE voltage below closed limit. 33 (rc*): Insufficient EGR flow detected. 34 (orc): EVP or PFE voltage above closed limit during operation. 34 (r): 2.3 Turbo. EGR On/Off not working. Insufficient EGR flow detected. 35 (orc*): EVP or PFE voltage above maximum limit during operation. 36 (r): Insufficient RPM increase, IVSC test. 37 (r): Insufficient RPM decrease, IVSC test. 38: Not defined for these applications. 39: Not defined for these applications. 41 (r): EGO/HO2S oxygen sensor voltage always below "lean" on bank #1. (c*): No EGO sensor rich/lean transitions detected, bank #1. 41 (c): 2.3 Turbo. EGO read lean for more than 15 seconds while in closed loop. 42 (r): EGO/HO2S sensor voltage always above "rich" on bank #1 (c*): No EGO sensor rich/lean transitions detected, bank #1. 42 (c): 2.3 Turbo. EGO read rich for more than 15 seconds while in closed loop. 43 (c): 2.3 Turbo. EGO read lean for more than 3 seconds at WOT. 44 (r): Thermactor air injection system inoperative, bank #1. Suspect AIR pump, diverter valve, solenoids, harness. 45 (r): Thermactor air is always upstream. Suspect diverter valve, solenoids, harness. 46 (r): Thermactor air unable to dump to atmosphere. Suspect diverter valve, solenoids, harness. 47 (o): Speed control command switches not working, IVSC test. 48 (o): Speed control command switches stuck/shorted to ground, IVSC test. 49 (o): Speed control ground circuit open, IVSC test. 51 (orc*): ECT voltage too high (coolant too cold, indicates -40degF!). Suspect possible shorted ECT, harness. 52 (o): PSPS (Power Steering Pressure Switch) circuit open. Suspect PSPS, harness. (r): PSPS did not change states. 53 (orc*): TP sensor voltage too high (indicates WOT condition). Suspect shorted TP sensor, harness. 54 (orc*): ACT (Air Charge Temperature)/IAT (Intake Air Temperature) sensor voltage too high, indidcating -40degF. Suspect shorted sensor, harness. 55: Not defined for this appication. 56 (orc*): MAF (VAF for 2.3 Turbo) sensor voltage too high. 57: Not defined for these applications. 58 (o): 1986+ 2.3 Turbo. ACT out of range. 58 (c): 1986+ 2.3 Turbo. VAT out of range (-40degF indicated). 59: Not defined for these applications. 61 (orc*): ECT voltage too low- indicates coolant temp greater than 250degF. 62: Not defined for these applications. 63 (orc*): TP sensor voltage too low. Suspect open TP sensor, harness. 64 (orc*): ACT/IAT (1984-84 2.3 Turbo, VAT) sensor voltage too low, indicates intake air temp greater than 250degF. 65: Not defined for these applications. 66 (rc*): MAF (2.3 Turbo, VAF) below minimum test voltage. 67 (o): Clutch switch open, AC left on, transmission in gear. 68 (oc): 1986+ 2.3 Turbo. VAT out of range (greater than 250degF indicated). 69: Not defined for these application. 71 (rc): 2.3L turbo only. PCM software reset detected- key power lost. Check PCM power harness. 72 (r): MAP sensor, insufficient vacuum detected during Dynamic Response test. 72 (c): 2.3 Turbo. VPWR (Vehicle power to EEC) intermittent. 73 (r): Insufficient goose during Dynamic Response test. Rerun test, goose it harder. 74 (r): BOO (Brake on/off) action not observed during Dynamic Response test. 75 (r): BOO switch always closed. 76 (r): 2.3L Turbo only. Insufficient VAF variation seen during Dynamic Response test. 77 (r): No goose detected during Dynamic Respose test. Rerun test, goose it harder. If this code is received during cylinder balance test, then a TP change was detected- rerun test, making sure not to disturb the throttle as it is running. 78: Not defined for these applications. 79 (o): A/C or defroster on durning KOEO. 81 (o): TAD or AM-2 (Thermactor Air Diverter)/ Secondary Air Injection Bypass (AIRB) solenoid circuit failure, or SCVNT (Speed Control Vent) circuit failure (IVSC test). 81 (o): 2.3 Turbo. Boost control circuit failure. 82: TAB or AM-1 (Thermactor Air Bypass)/ Secondary Air Injection Diverter (AIRD) solenoid circuit failure, or SCVAC (Speed Control Vacuum) circuit failure (IVSC test). 82 (o): 2.3 Turbo. Check EDF (Electro Drive Fan, electric engine cooling fan monitor) signal to PCM for short to ground. 83 (o): 2.3L Turbo only. Check for HEDF (High Speed Electro Drive Fan) signal to PCM for open circuit. 84 (o): EVR (EGR Vacuum Regulator) solenoid circuit failure. 84 (o): 2.3 Turbo - EGR Shut Off failure. Check for EGR solenoid open circuit. 85 (o): CANP (Canister Purge) solenoid circuit failure. 85 (o): 2.3 Turbo with Automatic (T-Bird). Check for 3-4 shift solenoid open circuit. 86: Not defined for these applications. 87 (oc): FP relay circuit failure- suspect inertia switch, fusible link, FP relay. 88 (o): 2.3 Turbo with Automatic (T-Bird). Check converter clutch override for open circuit. 89: Not defined for these applications. 91 (rc*): EGO/HO2S oxygen sensor voltage always lean, bank #2. Suspect vacuum leaks, EGR system, plugs, plug wires, EGO sensor. (c*): No oxygen sensor transitions detected, bank #2. 92 (r): EGO/HO2S voltage sensor always rich, bank #2. Suspect high fuel pressure, CANP problems, PCV problems, saturated EVAP canister, EGO sensor. 93: Not defined for these applications. 94 (r): Thermactor air injection system inoperative, bank #2. Suspect AIR pump, diverter valve, solenoids, harness. 95 (oc): Fuel Pump Monitor circuit problems, processor to pump motor ground. Suspect inertia switch, FP relay, harness. 96 (oc): FP circuit failure, battery to processor. 97: Not defined for these applications. 98 (r): Hard fault present. The PCM is running in FMEM (Failure Effects Management Mode), so something is royally screwed up that the KOEO test should have told you about. Rerun KOEO and fix whatever you find there. 99: Not defined for these applications. And there you have it. My fingers are _smoking_- that's enough for now.