Question about 1991 Volvo 940

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Thank you for reading this post. I am getting no ground signal from ECU. Pin 18 @ ecu found no resistance nor short to ground in harness. With ECU pluged in KEY ON and injectors unpluged I get batt voltage at injector grey/ground. My dvm pulls down voltage quickly 1 hudreth at a time till it zero out. I am suspecting a faulty ECU. #1 gn wire to injector is getting getting bat voltage. My concern is the ground. There is constant (KEY ON) bat volt to #2 grey. No pulse and no ground makes me suspect ECU. What is a good pin/bench test for this unit?

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Posted on Jan 02, 2017

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SOURCE: ECU appears to be dead

About a year or so ago, my 1991 240 Volvo was experiencing similar symptoms. Has this been an intermittent problem? (Sometimes starts, sometimes not?)
I looked at my fuses, especially fuse #6 which powers my fuel injector relay. With a friend, who is a professional mechanic, we determined fuel was getting to the injectors, but my coil spark was weak and injectors were not being pulsed. I wasted 300 dollars having the injector relay replaced, by another mechanic. Two weeks later, my car failed once again to start! It turned out to be a pitted connection at fuse #6! I inially just looked at the fuses, which were not blown, but when I took #6 out, it and the associated connector were pitted. Burnishing the connector and replacing #6 fuse has corrected this issue! If you haven't, pull your fuses, and inspect and clean the contacts! Maybe it's just that simple. Good Luck!!

Posted on Dec 19, 2008

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2 Answers

Ecm fuse problems


Well if you've had your ECM burn and got it changed and the same thing happen again then there might be a pilled positive wire exposed to the body or the chassis of your car touching at some point,my best advice is to trace all positive heavy wires leading from the starter and under the fuse board as well.i hope this helps thanks

Jun 23, 2014 | 2003 Ford F150 Regular Cab

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How to make your own O2 Sensor Simulator!


What is an O2 sensor simulator?
The OBD-II cars (1996-1998) have two O2 sensors to measure the amount of oxygen in the exhaust gas. First sensor is measuring it right after gases escape engine and this data is used to adjust fuel trim of the engine, as well as catch some faulty conditions. The second sensor is located after the catalic converter, and is used to detect the health of catalic converter. The ECU expects the signal from the sensor to be oscillating from below 0.4v to above 0.6v, but not above 1.2v, every few seconds while driving.

If you install an aftermarket downpipe with no cat (which is for off-road applications only) the ECU will detect this and indicate an error (MIL). The You can reset the ECU to clear the error code.

How to build Your Own Oxygen Sensor Simulator!
The rest of the page shows how to build an oscillating signal generator with just the right frequency and voltage to fool the ECU. It is based on classical astable operating mode of 555 timer.

Don't attach it directly to the ECU right after assembly. Instead attach it to the battery and check the output. You should get approximately 0v/0.7v flipping about every 3.3 seconds when the car is not running, and 0v/0.9v when the car is running. The current should stay below 10mA.

One LED should be always on whenever the power is supplied. Another LED indicates when the output signal is high, so it should go on and off with the signal.

When tapping the ECU wires, check everything before hooking up the oscillator. The power source should read 0v when the key is removed, about 12.6v when they key is at ACC and about 14.3 when the alternator is running. The resistance between ground wire and the body shield of the ECU should be 0 ohms. And it would be best if you run the car and monitor the voltage of the original oxygen sensor wire before cutting it to make sure you have indeed got the right one. The resistance between ECU PIN #47 and ground is about 1.3 to 1.6 M Ohm.

The original sensor should still be dangling around, or plugged into the downpipe. The reason is that ECU also monitors the resistance of heater circuit inside the sensor. If you want to COMPELTELY disconnect it, you will need to measure the resistance of the heater circuit and install the right resistor between ECU PIN #72 and ECU PIN #31 Anyway, there is no need to do it if you just leave O2 sensor alone and only intercept the oxygen signal wire.

Components
R1 100 K Ohm
R2 1 M Ohm
R3 100 K Ohm
R4 10 K Ohm
C1 4.7 uF
C2 22 uF
D1 1.7v@20mA LED
D2 1.7v@20mA LED
1020059.png
I assume no responsibility for any kind of damages.

on Jul 10, 2010 | Mitsubishi Eclipse Cars & Trucks

1 Answer

My 2005 jeep 4.0l has dtc 2302 , hesitates, replaced pcm still has code


replacing PCM is the last, why do that. which jeep,? wrangler? GC?
ECU is not bad and is almost always (GIGO) garbage in ,nets garbage out, now and for ever....
all most all errors are
1: input errors.
2: or bad output actuators or gee the engine it self.


now lets work
2302
ever see this>? or the FSM, the FSM book is way cheaper than any knee jerk ECU swap.. ouch.
http://engine-codes.com/p2302.html
out of FSM. actual
(F342) ASD OUTPUT CIRCUIT
(K19) COIL CONTROL 1 CIRCUIT OPEN
(K19) COIL CONTROL 1 CIRCUIT SHORTED TO GROUND
COIL
PCM (last ) never 1st ever....
so the coil pack is 4 pins and 3 coils, one one is hot key on.
the other 3 are 3 coils, coil 1 is bad,,
from a pure tech stand point its.
1: bad coil (open or shorted) bad wires, open or shorted or bad ECU.
we never condemn any ECU unless we do the simple lamp tests.
etc. case in point below.
here are the FSM steps, so easy to do.... (truncated, read your FSM)
1: coil 1 removed, connector.
key on is pin 2, 12v, if no fix that first. ( bad power distra. or fuse)
yes, 12v. so.
then, use a test lamp to pin 3 and ground
Pin 3 is COIL 1, !
crank car , does light flash? (any small 12v lamp works) 0.1 amps are less.
1: yes, flash PCM good, coil bad.
no?
test lamp tests continue....
2: stuck on lamp , wire is grounded out or bad PCM (pull PCM C2 conn, ? still tuck on?, yes, bad harness !
3: stuck lamp off? . this is harness wire cut or PCM bad.-
check continuity end to end on this wire. if good , bad ECU.
on a car with nice clean harnesses, no damage to conn?
its a bad coil.
the coil can in fact can be bench tested...
that to, is in the books.
(ohms tests, and make real spark) do so but do not exceed max dwell on the coil "smoke tested boom."( you need a pulse generator , or coil tester)
easy to make them .
there you go.... ECU last. for ever and ever.....

Sep 27, 2013 | Jeep Cars & Trucks

1 Answer

P0113 fault code at smog check


IAT (intake air temperature) sensor out of range.
It means that the ECU is reading low resistance. It could mean that you have a bad IAT Sensor, a bad ECU (Probably not), or an open (short) in the positive or ground.

Get a voltmeter. Unplug the IAT from the connector and hook the voltmeter to the positive and negative of the IAT sensor. Turn the key to the ON position (DO NOT turn the engine on). And measure voltage. It should be close to 5volts.

If you get close to 5 volts - Sensor is bad.
If you get 0 volts - Short in positive or ground wire.
If you get over 5 volts - Bad resistor in ECU

May 30, 2012 | 1997 Honda Civic

1 Answer

NEW CODE ON 2005 CHYSLER 300 0520 CAN NOT FIND WHY THIS CODE KEEPS COMING ON


Hi there:
DTC P0520 Engine Oil Pressure Sensor/Switch Circuit Malfunction

If you decide to replace it and the code returns once cleared.....then you will need to run the entire test for this code:
3_13_2012_4_18_24_pm.gif
Zoom link HERE
For a complete wiring diagram Refer to Section 8W.When Monitored:Ignition on, engine not running.Set Condition:The PCM senses the oil pressure is out of the calibrated range.Possible Causes(G6) ENGINE OIL PRESSURE SENSOR SIGNAL CIRCUIT SHORTED TO BATTERY VOLTAGERESISTANCE (G6) ENGINE OIL PRESSURE SENSOR SIGNAL CIRCUIT(G6) ENGINE OIL PRESSURE SENSOR SIGNAL CIRCUIT SHORTED TO GROUNDRESISTANCE IN (F856) 5-VOLT SUPPLY CIRCUIT(F856) 5-VOLT SUPPLY CIRCUIT SHORTED TO GROUNDRESISTANCE IN THE (K900) SENSOR GROUND CIRCUITENGINE OIL PRESSURE SENSORPCMAlways perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Diagnostic Test1. ACTIVE DTC NOTE: Ensure that the engine oil is at the proper level. Also, check the customers oil change history to ensure that the oil is being changed at the correct intervals and that the proper oil viscosity is being used.
Ignition on, engine not running.With a scan tool, read DTCs.Is the DTC active at this time?YesGo To 2
NoRefer to the INTERMITTENT CONDITION Diagnostic Procedure.


2. (G6) ENGINE OIL PRESSURE SENSOR SIGNAL CIRCUIT SHORTED TO BATTERY VOLTAGE
3_13_2012_4_19_33_pm.gif
Turn the ignition off.Disconnect the PCM harness connectors.Disconnect the Engine Oil Pressure Sensor harness connector. Ignition on, engine not running.Measure the voltage on the (G6) Engine Oil Pressure Signal circuit in the Engine Oil Pressure Sensor harness connector.Is the voltage above 0 volts?YesRepair the short to battery voltage in the (G6) Engine Oil Pressure Signal circuit.
NoGo To 3

3. ENGINE OIL PRESSURE SENSOR
3_13_2012_4_20_03_pm.gif
Turn the ignition off.Connect the PCM harness connectors.Ignition on, engine not running.With a scan tool, monitor the Engine Oil Pressure Sensor voltage. Connect a jumper wire between the (K900) Sensor Ground circuit and the (G6) Engine Oil Pressure Signal circuit.NOTE: Engine Oil Pressure voltage should change from approximately 4.5 volts to less than 0.5 of a volt.Is the voltage reading within the listed specification when the jumper wire is installed?YesReplace the Engine Oil Pressure Sensor.
NoGo To 4NOTE: Remove the jumper wire before continuing.

4. EXCESSIVE RESISTANCE IN THE (G6) ENGINE OIL PRESSURE SIGNAL CIRCUIT
3_13_2012_4_20_33_pm.gif
Turn the ignition off.Disconnect the PCM harness connectors.CAUTION: Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals resulting in poor terminal to pin connection. Install Miller Special Tool #8815 to perform diagnosis.
Measure the resistance of the (G6) Engine Oil Pressure Signal circuit from the Engine Oil Pressure Sensor harness connector to the appropriate terminal of special tool #8815.Is the resistance below 5.0 ohms for each circuit?YesGo To 5
NoRepair the excessive resistance in the (G6) Engine Oil Pressure Signal circuit.


5. (G6) ENGINE OIL PRESSURE SIGNAL CIRCUIT SHORTED TO GROUND
3_13_2012_4_20_55_pm.gif

Measure the resistance between ground and the (G6) Engine Oil Pressure Signal circuit Engine Oil Pressure Sensor harness connector.Is the resistance below 100 ohms?YesRepair the short to ground in the (G6) Engine Oil Pressure Signal circuit.
NoGo To 6

6. EXCESSIVE RESISTANCE IN THE (F856) 5-VOLT SUPPLY CIRCUIT
3_13_2012_4_21_24_pm.gif
Measure the resistance of the (F856) 5-volt Supply circuit from the Engine Oil Pressure Sensor harness connector to the appropriate terminal of special tool #8815.Is the resistance below 5.0 ohms?YesGo To 7
NoRepair the excessive resistance in the (F856) 5-volt Supply circuit.

7. (F856) 5-VOLT SUPPLY SHORTED TO GROUND
3_13_2012_4_21_54_pm.gif
Measure the resistance between ground and the (F856) 5-volt Supply circuit in the Engine Oil Pressure Sensor harness connector.Is the resistance below 100 ohms?YesRepair the short to ground in the (F856) 5-volt Supply circuit.Perform the POWERTRAIN VERIFICATION TEST.
NoGo To 8

8. EXCESSIVE RESISTANCE IN THE (K900) SENSOR GROUND CIRCUIT
3_13_2012_4_22_21_pm.gif
Measure the resistance of the (K900) Sensor Ground circuit from the Engine Oil Pressure Sensor harness connector to the appropriate terminal of special tool #8815.Is the resistance below 5.0 ohms?YesGo To 9
NoRepair the excessive resistance in the (K900) Sensor Ground circuit.Perform the POWERTRAIN VERIFICATION TEST.

9. PCMNOTE: Before continuing, check the PCM harness connector terminals for corrosion, damage, or terminal push out. Repair as necessary.
Using the schematics as a guide, inspect the wire harness and connectors. Pay particular attention to all Power and Ground circuits.Were there any problems found?YesRepair as necessary.Perform the POWERTRAIN VERIFICATION TEST.
NoReplace and program the Powertrain Control Module per Service Information.Perform the POWERTRAIN VERIFICATION TEST.

Hope this helps.

Mar 09, 2012 | 2005 Chrysler 300

2 Answers

Does anyone know what a transmission code 63 is for 1993 toyota t-100 with an a340e transmission? Thanks


On the a340e transmission that would be a shift solenoid circuit malfunction. You can purchase a "solenoid kit" that comes with two solenoids and mounting bracket, they can be easily replaced by dropping the transmission pan. They are attached with a single bolt (10mm)---Remove the bolt, unplug them from the wiring harness and pop them out of the ports they are seated in. Lightly coat the o-rings of the new solenoids with some ATF and insert them into their ports.
Good luck, i hope this helps.

Jul 24, 2011 | Toyota T100 Cars & Trucks

1 Answer

How do I wire a remote door lock to my 1995 mitsubishi eclipse , what are the wire colors for the power door locks?


Hope this helps. It's for a 2004 eclipse remote start.

12volts white/red (40A) + ignition harness
Starter black/red + ignition harness
Second Starter N/A
Ignition green + ignition harness
Second Ignition N/A
Third Ignition N/A
Accessory blue/red + ignition harness
Second Accessory blue/black + ignition harness
Keysense blue/red ignition harness
Notes: This wire rests at ground, and goes to an open circuit when the key is inserted into the ignition cylinder.
Power Lock purple - pin 33 at ETACS ECU
Notes: The ETACS ECU is attached to the back of the fuse box.
Power Unlock lt. green/red - pin 34 at ETACS ECU
Notes: The ETACS ECU is attached to the back of the fuse box.
Lock Motor lt. green 5wi pin 19, 28 pin plug below fuses
Unlock Motor green/red 5wi pin 22 at ETACS ECU
Notes: The ETACS ECU is attached to the back of the fuse box.
Parking Lights+ green/white + pin 2, 15 pin plug above fuses
Parking Lights- N/A
Hazards green - pin 55 at ETACS ECU
Notes: The ETACS ECU is attached to the back of the fuse box.
Turn Signal(L) green/blue + pin 8, 15 pin plug above fuses
Turn Signal(R) green/yellow + pin 13, 15 pin plug above fuses
Reverse Light red/blue + pin 9, 43 pin plug in driver kick
Door Trigger see notes - see notes
Notes: The driver door trigger is lt. green, pin 6, in a 15 pin plug above the fuses. The passenger door is lt. green/black in pin 65 at the ETACS ECU. Use both wires and diode isolate each.

The ETACS ECU is attached to the back of the fuse box.
Dome Supervision green/orange - pin 1, 3 pin plug above fuses
Trunk/Hatch Pin red - pin 62 or 37 at ETACS ECU
Notes: It is in pin 62 on the coupes, and in pin 37 on the convertible spyders.

The ETACS ECU is attached to the back of the fuse box.
Hood Pin green/red - pin 24 at ETACS ECU
Notes: The ETACS ECU is attached to the back of the fuse box.
Trunk/Hatch Release green/white 5wi pin 32 at ETACS ECU
Notes: The ETACS ECU is attached to the back of the fuse box.
Power Sliding Door N/A
Factory Alarm Arm lt. green/black - pin 42 at ETACS ECU
Notes: Meter this wire while turning the key in the driver door key cylinder.

The ETACS ECU is attached to the back of the fuse box.
Factory Alarm Disarm orange - pin 25 at ETACS ECU
Notes: Meter this wire while turning the key in the driver door key cylinder.

The ETACS ECU is attached to the back of the fuse box.
Disarm No Unlock blue/red - pin 27 at ETACS ECU
Notes: Meter this wire while turning the key in the hatch/trunk key cylinder.

The ETACS ECU is attached to the back of the fuse box.
Tachometer white or black/white ac engine speed detection connector
Notes: The engine speed detection connector is a single pin connector in the fuse/relay box under the hood.

Can also go to one of the ignition coils or the distributor assembly and use the black/blue or white/green wire.
Wait to start N/A
Brake Wire green/orange + brake pedal switch
Parking Brake yellow/green - parking brake switch
Horn Trigger lt. green/black - pin 44 at ETACS ECU
Notes: The ETACS ECU is attached to the back of the fuse box.
Memory Seat 1 N/A
Memory Seat 2 N/A
Memory Seat 3 N/A
Interface Module: Category:
Immobilizer Bypass Required:
Yes Type:
Transponder
Part #: 556UW
Alternate Part1 #: DesignTech 20402
Alternate Part2 #: DesignTech 29402
Notes: Standard on all models.

Good luck.

Mar 02, 2010 | 1995 Mitsubishi Eclipse

2 Answers

Jaguar xj6 4.0 1990. showing fault code fuel 14, fail 14. what does this code mean ?


2 airflow sensor out of operating range 3 coolant temp sensor out of operating range 4 oxy sensor indicates full rich 5 throttle potentiometer/airflow sensor... (low throttle pot signal with high airflow sensor signal) 6 throttle pot/airflow sensor...... (high throttle pot signal with low airflow sensor signal) 7 throttle pot...idle fuel adjustment failure(idle speed??) 8 intake air temp sensor...open or shorted circuit to sensor 11 Throttle pot at idle: Throttle pot idle trim out of normal range 12 Airflow meter: MAF signal out of range 14 Coolant thermistor: Resistance out of range or static during engine warm up 16 Air thermistor: Resistance out of range 17 Throttle pot: Out of range 18 Throttle pot/Airflow: Low throttle pot signal at high airflow 19 Throttle pot/Airflow: High throttle pot signal at low airflow 22 Fuel pump drive: ECU output to fuel pump relay 23 Fuel supply: Engine running too rich 24 Ignition Drive: ECU output to ignition Amp 26 Air leak: Engine running too lean 29 ECU self check 33 Injector Drive: ECU output to injectors 34 Injector: Looks for Injector dribble 37 EGR Drive: ECU output to EGR switching valve 39 EGR check sensor: EGR not working (normally pipe blocked) 44 Lambda (O2) sensor: Poor mixture control rich or weak (or misfire) 46 Idle speed Control valve: ECU output to Coil AB 47 Idle speed Control valve: ECU output to Coil CD 48 Idle Speed Control Valve: Stepper motor grossly out of position 66 Air pump: ECU output to air pump relay 68 Road speed sensor: Seen speed < 5km/h at high engine airflow 69 Drive/Neutral switch: Seen cranking in "D" or high airflow in "N" 89 Purge Valve drive: ECU output to purge valve
this is all I could find

Nov 09, 2009 | 1990 Jaguar XJ6

1 Answer

01 accent gl 1.6 liter auto,air ;engine lite on,trouble code 342, (cmp, sen low) three wire sys. posit 1 tests bat volt. posit 2 is suppose to read 0-5 volts @700-3000 rpm;but reads 12.1 running and 11.3...


P0342 is set when the ECM does NOT receive a signal from the CMP snsr. You may very well have GOOD continuity between the ECM and pin 2 (000.2 ohms), but that wire, if grounded someplace (shorted to ground or to another wire in the harness), the ECM will not/does not get a clear/proper signal. Look for a problem in the wiring harness.

Sep 03, 2009 | 2001 Hyundai Accent

3 Answers

1999 Hyundai elantra died while driving found ecu fuse blown replaced lasted half a mile and blew again


Check your o2 sensor harness. The harness if not properly secured will rub on the axle to a point where it rubs through the insulation of the wire & shorts on the axle causing the ECU fuse (20A) to blow. Repair the harness & replace the fuse & bada bing! You should be in business! Hope that works. IF NOT follow this K.I.S.S.

Keep It Super Simple! It never fails!

Jun 04, 2009 | Hyundai Motor 1999 Elantra

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