Car cranks and no sparks on coil, no OBD code?

2007 MAZDA 3
120,000 MILES • 2.3L • 4 CYL • 2WD • AUTOMATIC
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Hello,

My car won’t start but cranks, the issue started after it has been stalling for while driving or at idle and codes of lost communication e.g. (U0073, U0101, U0121, U0155), and the car will start immediately if I restart it. I cleared the codes and drove for some time, it will happen again and i will start again, now it won’t start at all but cranks and won't display any codes.
Some Checks already performed are:
1. Fuel pressure
2.coil
3. Spark plugs
4. Crankshaft sensor
5.injectors.
6. All Air intake sensors and possible leaks
7. All relays and Fuse Checked

They all check out to be fine except when cranking, the spark plugs and Injectors do not have ground from the PCM.
Am thinking of replacing the PCM but a check i need to perform last before that is testing the harness of the PCM to the instrument Cluster.

I need assistance for the instrument cluster terminal diagram, wiring and label to perform next check.

Thank you in Advance.
Apr 14, 2024 at 4:35 PM
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STRAILER
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Yep, this is a controller/module problem. But, because all of these modules share data with the PCM it would be the logical first choice.

U0073: Control Module Communication Bus "A" Off
U0101: Lost Communication with Transmission Control Module (TCM)
U0121: Lost Communication with Anti-lock Brake System (ABS) Control Module
U0155: Lost Communication with Instrument Panel Cluster (IPC) Control Module

Also, the fact that when you reset the system and it starts working again says PCM as well. You can get a preprogrammed unit by searching Google or Ebay. Check out the images (below). Please let us know what happens.

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Apr 15, 2024 at 9:56 AM
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i need to verify the wiring harness and pins that connect the ignition Coil and PCM along with the Instrument Cluster.

I don’t want to rush to replace PCM.
I once had a P0606 issues and replacing the PCM couldn’t solve the problem.

I need assistance as to have the pins labelling to perform the test.
Thank you
Apr 15, 2024 at 10:25 AM
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Sure, no problem, here is a guide to help you check the wiring and the engine/PCM wiring diagrams so you can see how the system works and high power and ground to check.

https://www.2carpros.com/articles/how-to-check-wiring

Check out the images (below). Please let us know what happens.
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Apr 16, 2024 at 9:02 AM
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I tried my best to check the igniters wire (GRN) to the PCM socket directly and there is no continuity to any of the PIN. I don’t know if i need to check continuity through the fuse or it should be directly but i did it straight from PCM harness pins to Coil connection

I replaced the PCM, and it couldn’t crank the car until it was programmed.

The new Scan shows all modules are okay except There’s a new code C1277 that came up under the ABS.

It keeps cranking and still no spark on the coil. Is it possible to have no spark when the timing is not accurate?
Apr 17, 2024 at 2:28 AM
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When you crank the engine over is the security light flashing? Also, the PCM must be programmed, did you get a pre-programed unit? Sounds like the PCM was the problem because the no communication codes have disappeared.
Apr 17, 2024 at 9:50 AM
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At first it flashes, then the PCM got programmed and it stopped. Attempt was made to start the vehicle but no changes from only Cranking and no spark.

I recently traced all the injectors, ignition coil, MAF, and IMRC wired to the PCM harness, and they all have a sound continuity.

Can crankshaft timing cause this to happen without throwing any code?
If yes, opening the engine is the last thing i want to do to fix this issue. So, did i miss out on any checks?
Apr 17, 2024 at 11:31 AM
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If you upload a short video of the engine cranking over, I can tell if it is hurt or not. You can do a compression test to see if the engine is okay as well. This will confirm the engine timing being the problem.

https://www.2carpros.com/articles/how-to-test-engine-compression

Please go over this guide and get back to us.

Apr 18, 2024 at 9:52 AM
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Hello sir, the timing is actually confirmed to be very good, we changed the camshaft sensor, and the car starts to ignite but still won’t start. It also displays EGR circuit failure P0403. I removed the EGR and cleaned it and it still won’t start, I later injected fuel directly through the throttle and crank the car then the car starts, Fuel pressure is okay but the four injectors are likely not sending fuel into the chambers. I check the ground wire and PCM wires and there is continuity to both, though multimeter did not detect any voltage coming from the signal of the PCM, does it mean that the PCM is replaced earlier is bad or it requires a better programming, assist me on what to do next. Thanks a lot
Apr 25, 2024 at 2:51 AM
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With the problem you are having and the fuses and grounds are good I would send the PCM and instrument cluster out for testing.
Apr 25, 2024 at 10:04 AM
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Okay, i later put back the old PCM and reprogrammed it but it only cranks and no spark at all. Am waiting for your instructions.
Apr 25, 2024 at 11:47 AM
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do you still have the codes? Can you clear the codes, and do they come right back? Please use a CAN scanner if you are not already.

You can get a CAN scanner (Controller Area Network) which will work on most cars from Amazon.

Here is a video to show you how:


https://youtu.be/u-4syLc-ifQ

and

https://www.2carpros.com/articles/can-scan-controller-area-network-easy

Please go over this guide and get back to us.
Apr 26, 2024 at 10:02 AM
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I called in a CAN scanner and all there is some codes about ABS and few for instrument clusters, then we decided to try a new PCM. The car will start but won't stay idling, tried to check the issue and it was found that only Injectors nozzle 1&2 are working. The rest have no voltage on the signal wire. The car will start now if the key is turned on to ignition twice and making the third turn to a start position. But it won't idle because it lacks enough fuel distribution.
May 2, 2024 at 2:00 PM
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Okay, for the injectors that are not working let;s use a voltmeter to check the OHMS readings. Here is a guide that will help with the testing. If you got 0 ohms, the injectors is bad.

https://www.2carpros.com/articles/how-to-test-a-fuel-injector

A shorted injector can take out the PCM. Check out the images (below). Please let us know what happens.
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May 3, 2024 at 12:12 PM
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I will perform the test. Update on the PCM, I replaced another PCM and it was supplying. Injectors 1&4 but 2&3 have no light on the test bulb. The car will start but quench between 5-8 seconds, but if i place my foot on the pedal, it runs till i let it go.
May 3, 2024 at 3:35 PM
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I performed the checked as you instructed. It all checked out fine. I also went ahead to perform as the workshop manual instructed and reads 12.5 ohm . What I couldn’t perfected is how to identify “MAIN RELAY terminal A”
Though i opened the fuse box under the hood by the driver side and i got continuity from some terminals including most fuses giving a beep sounds for continuity , Also checked main relay as designated on the fuse box cover label which i can’t verify if that’s the correct relay with terminal A to the Terminal B of the fuel Injector, though, one the terminals of that relay has continuity. All this test was performed without battery attached to the vehicle. Thank you.
May 4, 2024 at 7:45 AM
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The battery needs to be connected to the car to check for voltage. Also, was the fuel injector good?
May 4, 2024 at 8:35 PM
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That voltage test has been carried out since the beginning of the no crank. though i still did it again and i got 5v on 1 and 4 but no volt in 2 and 3.
May 4, 2024 at 10:29 PM