Symptoms of a bad or failing ignition relay

Nov 28, 2023

Kunle Shonaike

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Kunle Shonaike

The electrical architecture of a modern automobile is its lifeline. Contemporary vehicles are essentially electronic objects and the quality of its service in all its four main systemic compartments (power-train, body, chassis and communication protocol), like that of any electronic contraption, is dependent on its electrical fixtures: cables, relays, etc.

The ignition relay is one of the most important electronic relays found on modern vehicles. It is usually located in the fuse and relay panel beneath the bonnet, and is responsible for providing power to the vehicle's ignition system, and some of the fuel system's components. When the key is turned to the on position, the relay is switched on and power is directed to the vehicle's ignition and fuel system components, notably the fuel pump and ignition coils. When the relay fails or has an issue, it can cause major problems with the operation of the vehicle. Usually a bad or failing ignition relay will produce a few symptoms that can notify the driver of a potential issue.

Car suddenly stalls while operating: One of the most common symptoms of a failed ignition relay is a car that suddenly stalls while operating. If the ignition relay shorts, burns out, or otherwise fails while the engine is operating it will cut off power to the fuel pump and ignition system. This will cause the vehicle to immediately stall due to fuel and spark being cut off. In some instances of a faulty relay, the vehicle will be able to restart once the relay cools off, only to stall out once again after the relay overheats.

Car not starting: Another symptom of a faulty ignition relay is a no power condition. If the relay fails it will cut off power to fuel pump and ignition system, which will result in a no power, and therefore no start condition. You may find that turning the key may power on the accessories, and may even crank the engine. However, the vehicle will not start due to their not being any power directed to the fuel and ignition system. Similar symptoms can also be caused by a wide variety of other issues, so a proper diagnosis is recommended in order to make certain what the issue is.

Dead battery: A dead battery is another symptom of a faulty ignition relay. If the relay has an internal short, it may keep power fed to the ignition and fuel system, even when ignition cylinder is in another position, or the key is removed. This will cause the fuel pump and ignition components to remain powered on, drawing current, at all times, which will eventually lead to a dead battery. Aside from draining the battery, this may also cause accelerated wear on the components, notably the fuel pump, due to having them powered on, but not operating.

Burned relay: In certain instances, it may be possible for the relay to overheat to the point of burning up and melting. Apart from cutting off power to the vehicle's ignition relay and causing performance issues, a burnt relay may melt onto the fuse panel. This may make it difficult to remove, and in some instances can even lead to the replacement of the entire fuse box.

While servicing the ignition relay is not generally considered a routine maintenance, it can sometimes fail and cause major issues for the vehicle. If you suspect that your ignition relay may be having an issue, have the vehicle inspected by a professional technician.

NB: Parts of this piece is culled from the Internet.

Feedback

In a failing car engine that is losing oil and being topped up with new oil, is there any benefit to servicing, especially the oil change part?

Secondly, if you say there isn't, can I do an oil filter change at recommended intervals only and forgo the oil change? Please advise me. Nich

It depends on how bad the engine is losing oil; is it losing the engine oil through leaking or smoking? Though you said smoking, if the smoking is as a result of bad valve stem seal you can replace the seal by doing a complete valve train repair or rebuild the engine if it is as a result of worn out oil rings and cylinder walls.

Yes you can replace just the filter alone if you are using up to four litres of oil a week.

What is your take on making a choice between V6 and V4 engine cars and SUVs? I am asking because most people advise that buying a V4 engine vehicle saves cost of fuelling, while V6 cars consume fuel. Onuoha

Yes they are right. Also, you have to think of maintenance; it's cheaper to maintain four cylinders than a V6 engine.

Please what could be the problem with my Kia Sorento 2.4L engine? The car would not rev up to 3000rpm and the check engine light is not on. On scanning the car, the following codes were reported P0222, P0076, P0652, P2110, P2106, P0123, P0453. Please advise. Anonymous

Someone must have blocked or removed the check light, because with all the codes you have, the light should be on. Below are the interpretations of the codes. But the main ones that concern the challenges you are dealing with are P0222, P2106 and P2110. Your technician should be able to use them to solve the fault.

P0076 KIA: Intake valve control solenoid circuit low bank 1

Intake valve timing control solenoid valve is activated by on/off pulse duty (ratio) signals from the engine control module.

The intake valve timing control solenoid valve changes the oil amount and direction of flow through intake valve timing control unit or stops oil flow.

The longer pulse width advances valve angle. The shorter pulse width retards valve angle. When on and off pulse widths become equal, the solenoid valve stops oil pressure flow to fix the intake valve angle at the control position.

When is the code detected?

An improper voltage is sent to the engine control module through intake valve timing control solenoid valve.

Possible causes

P0123 KIA: Throttle/pedal position sensor ‘A’ circuit high input

The throttle position sensor responds to the accelerator pedal movement. This sensor is a kind of potentiometer which transforms the throttle position into output voltage and emits the voltage signal to the engine control module. In addition, the sensor detects the opening and closing speed of the throttle valve and feeds the voltage signal to the ECM.

Idle position of the throttle valve is determined by the ECM receiving the signal from the throttle position sensor. This sensor controls engine operation such as fuel cut. On the other hand, the wide open and closed throttle position switch, which is built into the throttle position sensor unit, is not used for engine control.

When is the code detected?

The throttle position sensor signal 1 circuit has reported a high voltage

Possible causes

P0222 KIA: TPS/Pedal position sensor/Switch ‘B’ circuit low input

Electric throttle control actuator consists of throttle control motor, throttle position sensor, etc. The throttle position sensor responds to the throttle valve movement.

The throttle position sensor has the two sensors. These sensors are a kind of potentiometers which transform the throttle valve position into output voltage, and emit the voltage signal to the engine control module. In addition, these sensors detect the opening and closing speed of the throttle valve and feed the voltage signals to the ECM. The ECM judges the current opening angle of the throttle valve from these signals and the ECM controls the throttle control motor to make the throttle valve opening angle properly in response to driving condition.

When is the code detected?

An excessively low voltage from the throttle position sensor is sent to engine control module.

Possible symptoms

Possible causes

P0652 KIA: Sensor reference voltage ‘B’ circuit low

The control module has two internal five-volt reference buses called five-volt reference 1 and five-volt reference 2 . Each reference bus provides 5-volt reference circuit for more than one sensor. Therefore, a fault condition on one five-volt reference circuit will affect the other five-volt reference circuits connected to the reference bus. The control module monitors the voltage on the five-volt reference buses.

When is the code detected?

The engine control module has detected the sensor five volt reference circuit voltage is lower than expected

Possible causes

P0453 KIA: EVAP emission system pressure sensor high input

The evaporative emission system control system pressure sensor detects pressure in the purge line. The sensor output voltage to the engine control module increases as pressure increases. The EVAP control system pressure sensor is not used to control the engine system. It is used only for on board diagnosis.

When is the code detected?

An excessively high voltage from the sensor is sent to engine control module.

Possible causes

P2106: Throttle actuator control system – Forced limited power

The throttle actuator control system uses vehicle electronics and components to calculate and control the position of the throttle blade. This eliminates the need for a mechanical cable attachment from the accelerator pedal to the throttle body. This system also performs the cruise control functions as well.

The TAC system components include, but are not limited to the following:

– The accelerator pedal position sensors

– The throttle body

– The power-train control module

Each of these components interfaces together to ensure accurate calculations and control of the throttle position.

Throttle body assembly

The throttle body for the throttle actuator control system is similar to a conventional throttle body with several exceptions. One exception is the use of a motor to control the throttle position instead of a mechanical cable. Another exception is the throttle position sensor. The TP sensor is mounted in the throttle body assembly. The TP sensor is two individual TP sensors within the throttle body assembly. Two separate signal, low reference, and five-volt reference circuits are used to connect the TP sensors and the power-train control module. TP sensor 2 signal voltage increases as the throttle opens. TP sensor 1 signal voltage decreases as the throttle opens.

Possible causes

P2110: Throttle actuator control system – forced limited engine speed

The throttle actuator control system uses vehicle electronics and components to calculate and control the position of the throttle blade. This eliminates the need for a mechanical cable attachment from the accelerator pedal to the throttle body. This system also performs the cruise control functions as well.

The TAC system components include, but are not limited to the following:

– The accelerator pedal position sensors

– The throttle body

– The power-train control module

Each of these components interface together to ensure accurate calculations and control of the throttle position.

Throttle body assembly

The throttle body for the throttle actuator control system is similar to a conventional throttle body with several exceptions. One exception is the use of a motor to control the throttle position instead of a mechanical cable. Another exception is the throttle position sensor. The TP sensor is mounted in the throttle body assembly. The TP sensor is 2 individual TP sensors within the throttle body assembly. Two separate signal, low reference, and 5-volt reference circuits are used to connect the TP sensors and the power-train control module. TP sensor 2 signal voltage increases as the throttle opens. TP sensor 1 signal voltage decreases as the throttle opens.

Possible causes

Please, I have a Toyota Corolla car, 2012 model 1.8L capacity.

Recently, it started showing ‘check engine’ with warning lights.

Please advise me on this. Thank you.

My advice will be to run a scan on the power-train system. The results will reveal or guide on what to do.

P0593: Speed control switch 2 circuit high

The engine control module monitors the speed

Speed control switch 2. The ECM sets the OBDII code when the speed control switch 2 is not to factory specifications.

When is the code detected?

The ECM has detected that the speed control switch 2 is above minimum voltage range

Possible causes

Faulty speed control switch speed control switch harness is open or shorted speed control switch circuit poor electrical connection

P0594: Cruise control servo control circuit/open

The engine control module monitors the cruise control servo. The ECM sets the OBDII code when the cruise control servo is not to factory specifications.

When is the code detected?

Open or shorted condition in the cruise control servo circuit

Possible causes

Faulty servo motor servo motor harness is open or shorted Servo motor circuit poor electrical connection

P0595: Speed control servo control circuit low

The engine control module monitors the cruise control servo. The ECM sets the OBDII code when the cruise control servo is not to factory specifications.

When is the code detected?

Open or shorted condition in the cruise control servo circuit

Possible causes

Faulty servo motor servo motor harness is open or shorted Servo motor circuit poor electrical connection

P0596: Speed control servo control circuit high

The engine control module monitors the cruise control servo. The ECM sets the OBDII code when the cruise control servo is not to factory specifications.

When is the code detected?

Open or shorted condition in the cruise control servo circuit

Possible causes

Faulty servo motor servo motor harness is open or shorted Servo motor circuit poor electrical connection.

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All rights reserved. This material, and other digital content on this website, may not be reproduced, published, broadcast, rewritten or redistributed in whole or in part without prior express written permission from PUNCH.

Contact: [email protected]