Question about 2003 GMC Sierra

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Cannot get engine to start. In checking, the ignition coils are not being energized. What may be the problem?

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Possible crank sensor not giving a pulse for the computer recognize. So it won't energize the coils.

Posted on Oct 04, 2009

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Posted on Jan 02, 2017

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Error Code P0351 for a 2005 Toyota Avalon


Possible causes
Faulty Ignition Coil 1
Ignition Coil 1 harness is open or shorted
Ignition Coil 1 circuit poor electrical connection
Faulty Engine Control Module (ECM)

What does this mean? When is the code detected? Each ignition circuit is continuously monitored by the Engine Control Module (ECM). The test fails when the ECM does not receive a valid pulse signal from the ignition coil. Possible symptoms Engine Light ON (or Service Engine Soon Warning Light) Lack/Loss of Power Engine may be harder to start Engine hesitation Rough engine idle P0351 TOYOTA Description: The ignition system on the vehicle uses individual ignition coils for each cylinder. The Engine Control Module (ECM) controls each ignition coil operation. The ECM sends a ON/OFF signal to energize the ignition coil to create a spark at the spark plug when a spark is required at the cylinder.

May 29, 2017 | Toyota Cars & Trucks

1 Answer

What would cause a coil to burn out on a Mazda Tribute 05 v6


Ignition coils fail due to bad spark plugs or plug wires. Another potential cause is heat and vibration, which can damage the ignition coil's windings and insulation. If an engine is experiencing repeated coil failures, the underlying cause may be resistance from worn spark plugs or excessive spark plug gap. And in rare cases, the failure may be due to a lean fuel condition caused by leaky valves.

With coil on plug (COP) type coils, the rubber insulation dries up (over time and heat from the engine) and cracks and will arc across the engine's metal- shorting out. (Electricity seeks the path of least resistance)

By design, coils take low voltage energy from the battery (12-Volts dc) and transform that energy into a very high voltage charge (in the range of 30,000 to 35,000 volts) to energize the spark plugs which in turn ignites the fuel.

If a spark plug or plug wire is open or has excessive resistance, the ignition coil's output voltage can shoot higher (above the max threshold of 35,000 volts) and burns through the coil's internal insulation, causing a short.

When a coil failure occurs, the coil's voltage output drops, and the engine may not start or may misfire badly when under load.

Extreme caution should be exercised when handling coil packs that are energized- a lethal dose of voltage can arc across the air into the body. So don't touch them when the engine is running!

As stated earlier, if you need to replace the COP, replace the spark plug too, make sure the spark plug is properly gapped.

You can read more about coils here:

Ignition Coil High Voltage Display

Feb 05, 2017 | 2005 Mazda Tribute

1 Answer

?Had a new starter and new battery put on my 1999 Chevy Tahoe.. we by it starts sometimes and sometime it don't..what could the problem be


I'm assuming just by the fact you had a new battery and new starter that sometimes when you turn the key to the start position , nothing happens . Is your vehicle a automatic transmission ? When it doesn't start have checked for battery voltage at the starter solenoid S terminal ? Is there B+ voltage at pins 30 & 86 for the starter relay ? Pin 86 while cranking the engine or trying to crank the engine over . Pin 30 check with key on . Try moving gear selector to neutral . Videos on youtube for basic automotive electrical testing . How to voltage drop test starter motor circuit Find a wiring diagram at www.bbbind.com
Starting System Circuit Description
Voltage is applied at all times to the ignition switch from the IGN A fuse 6 through CKT 242 (RED). When the ignition switch is turned to the START position, voltage is applied to the CRANK fuse 8 through CKT 5 (YEL). From the CRANK fuse 8, voltage is either applied to the clutch pedal position switch (M/T) or the transmission range switch (A/T) through CKT 806 (PPL). When either the clutch is disengaged (M/T) or the transmission is in park or neutral (A/T), voltage is applied to the coil of the starter relay through CKT 1035 (PPL/WHT). Since the starter relay is permanently grounded at ground G105 through CKT 150 (BLK), the starter relay energizes.
Voltage is applied at all times to the starter relay contacts from IGN A fuse 6 through CKT 242 (RED). When the starter relay energizes, the starter relay contacts close, and voltage is applied to the starter motor solenoid. Since the starter motor solenoid is permanently case grounded, the starter motor solenoid will energize two coils. The pull-in winding coil energizes in order to pull the starter motor solenoid contacts closed. When the contacts close, a plunger on the contacts causes the pull-in winding coil circuit to open. The hold-in winding coil then holds the starter motor solenoid contacts closed. Voltage is then applied to the starter motor from the battery through CKT 1 (BLK) and the closed contacts of the starter motor solenoid. Since the starter motor is also permanently case grounded, the starter motor will run until the ignition switch is moved out of the START position. When this happens, a spring in the starter motor solenoid moves the starter motor solenoid contacts and the plunger back to the rest position.

Jan 07, 2017 | 1999 Chevrolet Tahoe

1 Answer

Engine cold. Start engine reading says engine hot ac off. Fans run all time.


Are the fans running on low or high ?
Circuit/System Description
The engine control module (ECM) commands the fans ON in either high speed or low speed, depending on cooling requirements. In low speed, both fans are turned ON at a reduced speed. High speed has both fans turned ON at full speed.
In low speed operation, the ECM applies ground to the coil side of the fan low relay. This energizes the coil and applies voltage directly to the left cooling fan through the switch side of the fan low relay, which is fed by the fan 1 fuse. The right fan is connected in series to the left fan through the de-energized fan control relay so that both operate at low speed.
In high speed operation, the ECM applies a ground to the coil side of the fan low relay, the fan control relay , and the fan high relay. On the fan high relay, the energized coil closes the switch side of the relay and applies voltage directly to the right cooling fan through the switch side of the relay, which is fed by the fan 2 fuse. At the same time, the ECM energizes fan control relay pulling the switch side over, providing a direct path to ground for the left cooling fan, which has voltage applied through the energized fan low relay. In high speed mode, the fans are operated as a parallel circuit with full voltage applied to each.
You should have it hooked up to a scan tool that can read engine sensor data parameters . Check for DTC'S - diagnostic trouble codes etc...
Circuit/System Verification
  1. If DTCs P0480 or P0481 are set, perform those diagnostics first.
  2. Ignition ON, verify with a scan tool that the control module is not commanding fan activation.
  3. Ignition ON, observe that the fans are not activated.
Your best bet is to take it to a ASE certified repair shop !

Jan 10, 2016 | 2009 Chevrolet Silverado 1500

1 Answer

I have no spark to or from coil


Hi Rick, I'm glad to help! Rick, the PCM which is the Engine Controller must see a signal from the crankshaft position sensor and the camshaft position sensor before it will energize the ASD which is the Auto-Shut-Down-Relay. Which when energized then activates the spark to the coil pack. NOTE: Let's say the PCM is seeing the signal and is energizing the ASD but nothing is happening. If thats the case? FIRST: Try switching the ASD relay with another one just like it and see if it starts. If it doesn't, check every fuse under the hood and inside the vehicle. If they are all good. Then make sure there is power coming from the ignition switch to the ASD relay. Turn the key to the start position and see if the test light lights up. If it does then Replace the "Crank Sensor" first and see if it starts. If it still doesn't start then Replace the "Cam Sensor" If it still doesn't start. Then your into either a wiring problem somewhere or the PCM is bad. CAUTION: You must check every other possibility before replacing the PCM, because its very expensive. Hope this helps and have an awesome day Rick.

Apr 07, 2014 | 2005 Dodge Neon

1 Answer

1999 GMC Sonoma 2.2L will not start.


What is wrong????????? That would be a guess on anyones part here ! Testing the electrical circuits involved would be the proper way to diagnose this no start problem ! Using a volt meter an wiring diagram to check voltage at different point's in the starter circuit . voltage drop testing ! Plus knowing how the starter system works !
Starter Circuit Operation
Voltage is applied at all times to the ignition switch from the IGN A fuse through CKT 42 (RED). When the ignition switch is turned to the START position, voltage is applied to the CRANK fuse through CKT 5 (YEL). From the CRANK fuse , voltage is either applied to the clutch pedal position switch (M/T) or the park/neutral position switch (A/T) through CKT 806 (PPL). When either the clutch is disengaged (M/T) or the transmission is in park or neutral (A/T), voltage is applied to the coil of the starter relay through CKT 1035 (PPL/WHT). Since the starter relay is permanently grounded at ground G102 through CKT 150 (BLK), the starter relay energizes.
Voltage is applied at all times to the starter relay contacts from IGN A fuse through CKT 42 (RED). When the starter relay energizes, the starter relay contacts close, and voltage is applied to the starter motor solenoid. Since the starter motor solenoid is permanently case grounded, the starter motor solenoid will energize two coils. The pull-in winding coil energizes in order to pull the starter motor solenoid contacts closed. When the contacts close, a plunger on the contacts causes the pull-in winding coil circuit to open. The hold-in winding coil then holds the starter motor solenoid contacts closed. Voltage is then applied to the starter motor from the battery through CKT 1 (RED) and the closed contacts of the starter motor solenoid. Since the starter motor is also permanently case grounded, the starter motor will run until the ignition switch is moved out of the START position. When this happens, a spring in the starter motor solenoid moves the starter motor solenoid contacts and the plunger back to the rest position.


Starter Voltage Drop

How to voltage drop test starter motor circuit

Jun 23, 2017 | 1999 GMC Sonoma

1 Answer

What it means code po352


Here is the definition of the code.

P0352 FORD Description The ignition system on the vehicle uses individual ignition coils for each cylinder. The Engine Control Module (ECM) controls each ignition coil operation. The ECM sends a ON/OFF signal to energize the ignition coil to create a spark at the spark plug when a spark is required at the cylinder.
Read more: http://engine-codes.com/p0352_ford.html#ixzz274FH7g9Y

Sep 20, 2012 | Ford Cars & Trucks

2 Answers

My ASD fuse is making a clicking noise and vibrating. What is the function of this fuse?


ASD fuse is called an AUTOMATIC SHUT DOWN FUSE. The ASD sense circuit informs the PCM when the ASD relay energizes. A 12 volt signal at this input indicated to the PCM that the ASD has been activated. This input is used only to sense that the ASD relay is energized.
When energized, the ASD relay supplies battery voltage to the fuel injectors, ignition coils, and the heating element in each oxygen sensor. If the PCM does not receive 12 volts from this input after grounding the ASD reley, it sets a Diagnostic Trouble Code (DTC).

May 18, 2011 | Jeep Cherokee Cars & Trucks

2 Answers

'91 Blazer won't start


then the problem lies in your ignition relay. even though your rotor is spining there is no current to energize the coil. when you turn the key the relay closes and allows the voltage of tha battery to flow and energize the coil.

Apr 19, 2009 | 2000 Chevrolet S-10

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