Question about Cars & Trucks
1987 nissan d21 v6 4x4, I get 4 short green led flashes when I run the diagnostics on the ecu. What does that mean? Could that indicate a bad ignition control module? This truck shuts down and not start after warming up for a few minutes.
The vehicle uses flashing led's to represent faults as it is prior to 1988 when OB system came into place . You will have to contact the dealer service centre to find what the flashes mean as a code or failure of a sensor.
Posted on Feb 16, 2014
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Posted on Jan 02, 2017
Best to do a fuel pressure test, pump might be weak and dosent show up until it gets gets warm. Best to do the test after it quits again when pump is at its hottest. If you havent done it yet chg. fuel filter too.
Posted on Mar 26, 2009
fuel pump and fuel sock is bad replace them but first replace the fuel filter, it's located driverside on the inside of frame rail under door.
Posted on Aug 14, 2009
The fuel pump relay is burried under the dash. The new one will help you find the old one. It is bigger than e regular relay.
It is on the drivers side Ithink.
If you don't hear the pump when you turn the key it will never start. All of those relays fail because these cars outlast them.
Posted on Dec 09, 2009
On some models, the Engine Control unit has a power supply relay. These relays some times get internal dry solder points. After driving for some time the the solder will get hot and separate. When it cools down it makes contact again. You will have to replace this relay or open it up and re- solder the solder joints. The relay is usually located on the main relay station in position 3. the relay station is located behind the right dash panel.[right hand drive vehicles]. You may need to refer to a manual for your specific model to find the exact location of the relay.
Posted on Jun 04, 2010
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READING CODES Modes will not switch while the engine is running. The ECM automatically switches to MODE I when the ignition is switchedOFF.
1984-90 Vehicles With Dual LED System
The self-diagnostic system has 5 modes. To switch modes, switch the ignition ON and use a screwdriver to turn the mode select switch through the access port on the ECM. The inspection lights will begin to flash. When the desired mode has been entered, turn the screwdriver fully counterclockwise. The red LED and green LED perform different functions in different modes.
This is the normal vehicle operating mode. The green LED will indicate loop status. If the green LED is not blinking when the engine is running, the vehicle is in open loop, or the HO 2 S, O 2 S, or sensor circuit has a malfunction. If the green LED is blinking, the vehicle is in closed loop. If a malfunction takes place, the red LED and the MIL will glow, indicating a malfunction has occurred.
Both the red LED and green LED are used to monitor mixture ratio feedback control. The green LED will function as described in MODE I. If vehicle is in open loop, the red LED and green LED will remain on or off. In order for results to be valid, vehicle must be in closed loop. In closed loop, the red LED remains off if the system is running rich, comes on if the system is running lean, and blinks at the same time with the green LED if system is within 5% of the exact air/fuel ratio.
-When this mode is accessed, the codes stored in the ECM's memory will be flashed by the green LED and red LED on the side of the ECM. The red LED will light first. This is the first digit of the trouble code; the green LED will flash next, showing the second digit of the code. For example: 2 flashes of the red LED followed by 1 flash of the green LED corresponds to Code 21.
This mode is used for checking the throttle plate (TP) switch, starter, and vehicle speed switch status. When the TP switch or starter switch is activated, the red LED will briefly flash as the status changes. For VSS status, the green LED will remain off when vehicle speed is less than 12 mph (19 km/h) and come on when vehicle speed is greater than 12 mph (19 km/h).
This mode represents a real-time diagnostic test of the crank angle sensor, ignition signal and the mass airflow signal. The malfunction code will be displayed only when the malfunction occurs and will not be stored in memory. The output code will appear as a single or short string of pulses. Count the number of pulses for the malfunction code.
1 pulse-CMP sensor signal lost or noise in signal 2 pulses-MAF Sensor signal abnormal 3 pulses-Fuel pump circuit shorted or open 4 pulses-Ignition signal lost
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