No Start Issues

Check communication with the following ECU’s:

ECM/PCM
TCM (e.g. park/neutral position signal, …)
Anti – Theft ECUs (Immobilizer, Steering Lock, BCM…)
Air Bag module (e.g. ‘Crash Signal’ on [Land Rover, Volvo, Mercedes])
- 📝 No Start | Crash Signal Crash Signal | 2015 Mercedes C350
  - Xentry → Engine ECU → Adaptations → “start disabled due to crash event”
  - This will lift the lock …you may get an error saying it hasn’t completed, ignore it as it has done it (DK)
ABS Module
- On some cars (e.g. 2007 Volvo S80), no communication with the ABS module will result in a no start condition
- On other cars, ABS can be a part of immobilizer system (e.g. 2019 Honda Accord)
Radio Transceiver
- 📝 No Start | Radio Transceiver Disconnected | 2014 Ford Fusion
  - With radio transceiver module car won’t start and ignition won’t turn on. Its located on headliner.

Anti – Theft Related (Immobilizer)
- Key Programming, Security Components Matching, Aftermarket Alarm Interference, Remote Shut-off Devices, etc.

Safety Related
- TCM
  - Transmission codes might cause a no-start
  - Park/Neutral Position Switch signal (tells ECM if transmission is in PARK).
- Air Bag module (e.g. ‘Crash Signal’ on [Land Rover, Volvo, Mercedes])
- ABS
  - On some cars (e.g. 2007 Volvo S80), no communication with the ABS module will result in a no start condition
  - On other cars, ABS can be a part of immobilizer system (e.g. 2019 Honda Accord)
- Fail-Safe Mode
  - Hold brake pedal and start button for a minute (e.g. 08′ Prius)
  - Check codes in ECM and TCM
Emissions Related
- DEF (Diesel Exhaust Fluid, e.g. AdBlue)
  - If the DEF system has malfunction, it might start a countdown of remaining starts. That is when you are expected to fix the problem. If not fixed, car will stop starting. Dealer usually has a scan tool option (for a last chance DEF repair) to reset it for another 5 or so starts. If you run out of starts then, you might need to buy a brand new ECM.
- Exhaust Gas Temperature Sensor codes (e.g. Ford Diesel)
- Bad/Disconnected Coil might cause a no-start (e.g. 07′ Toyota Sienna)

➱ Ignition Troubleshooting
➱ Timing Troubleshooting
- CKP and CMP sensors signals or their correlation.
- Note that ECM might not give a code about wrong timing (e.g. 14′ Ford Focus, …)
- Timing belt or Chain [Loose/ Jumped/ Broken]

Testing:

Scope CKP and CMP. Compare the waveform with a known good one.
Use Oscilloscope, Ignition Pickup Probe (e.g. COP or secondary ignition probe), and Pressure Transducer (e.g. WPS500X). Waveform will show a spark in relation to compression stroke. Spark should align with the tip of compression. If it is shifted, timing is off. (https://www.youtube.com/watch?v=bmIEbnglVj0)

ECT (Engine Coolant Temperature Sensor).
- ECM uses Engine Coolant Temperature sensor in calculation of air/fuel ratio.
- 07′ Toyota Sienna. Unplugged ECT can cause a no start.
O2 Sensor
- 15′ Focus 2.0 GDI. Car failed to start (almost started), but felt like it lacked fuel. After the front O2 has been disconnected, started right up.
High Side Fuel Pressure Rail Sensor
- 2013 Scion FRS. Start and stall scenario. Disconnected front O2, started, but stalled on pressing the gas pedal. After a while it stopped starting at all. After “High Side Fuel Pressure Rail Sensor” replacement, everything started to work properly.
- 2013 Jetta TDI

Testing:

Testing:

Low Compression
- Blown head gasket
  - Note, compression test is inconclusive! It can have good compression on all cylinder with coolant leaking. Check coolant level, or ask customer he refilled coolant.
- Bent con rod, worn piston rings
- Intermittent compression?
  - Variable Valve Actuation assembly (e.g. 15′ Jeep Cherokee, Fiat 500 with MultiAir System)
    - → Variable Valve Actuation assembly (Fiat 500 with MultiAir System)
Seized engine

Testing: