Toyota Tundra Ignition Coil Problems

The Toyota Tundra, a powerhouse of a pickup truck known for its rugged durability and impressive towing capacity, has long been a favorite among truck enthusiasts. However, even the most reliable vehicles can experience issues, and in the case of the Toyota Tundra, ignition coil problems have been a recurring concern for many owners. 

Some of the common Toyota Tundra ignition coil problems reported by users include sudden loss of power, cracks in the ignition coil, dying off of the vehicle, and misfiring. 

Whether you’re an avid off-roader or rely on your Tundra for heavy-duty work applications, or else you’re planning a brand-new one, understanding these issues in Toyota Tundra is essential for maintaining your truck’s peak performance and reliability. So, let’s explore them in detail. 

Toyota Tundra Ignition Coil Problems

Toyota Tundra Ignition Coil Problems

Now, let’s dig deeper into the common ignition coil problems faced by Toyota Tundra owners. 

1. Loss of Power

A substantial portion of Toyota Tundra owners have raised concerns over experiencing a decrease in vehicle power. This is frequently spotlighted as one of the prevalent Toyota Tundra ignition coil problems. The most common preliminary diagnosis advises for the replacement of the faulty coil along with spark plugs at the 2 and 3 cylinders, seen as a typical remedial action.

However, this solution doesn’t appear to be long-lasting, with several Tundra owners revealing that this particular problem resurfaces after time. Their first-hand experiences report that initially, their vehicle embarks in a seemingly normal state. 

But shortly after clocking just half a mile, they encounter an appreciable drop in power output, which gives them the sensation of their car running merely on 2 cylinders. Also, the experience is akin to a stunted acceleration, making the ride less smooth and significantly slower.

Now, speaking honestly, this issue does not stem solely from the coil itself but the rubber boot and spring that interface with the spark plug. The deterioration or fracturing of the rubber boot can lead to misfires. 

Economically speaking, it’s prudent to substitute the boots and springs during a spark plug replacement cycle. A vast majority of professional service centers will opt to replace the entire coil unit, which includes a new boot and spring. 

2. Car Dies When Gets Hot

Many owners of older Toyota Tundra vehicles, particularly those dating back to 2000, have been experiencing a perplexing issue. They report that when the vehicle heats up, the engine suddenly shuts off without warning. Despite this, no OBD II errors are detected, and the check engine light remains unilluminated. 

Although the ECM fuse occasionally blows, replacing it does not resolve the issue, and the vehicle remains inoperable until the engine compartment cools down. Despite evidence of a spark from the plugs and fuel pressure in the rail, exhaustive attempts to rectify the problem by replacing relays and fuses have led to suspicions that the root cause may lie with the ECM controller itself. 

The recent recall of ECM units for Matrix and Corolla models suggests that similar issues might have been present in Tundra vehicles for a significant period. This problem has persisted for over five years, with Toyota dealers and specialized shops unable to identify any codes or find a solution due to its intermittent nature and ability to function normally after cooling down.

3. Cracks in the Ignition Coil

Some Toyota Tundra owners, particularly those with the 2006 model, have encountered a rare issue involving cracks in the ignition coil. One of the primary factors contributing to these cracks is driving with worn-out spark plugs. 

When 40,000 volts are sent through a plug with an excessively wide gap, the voltage may attempt to breach the side of the coil, resulting in overheating and, in severe instances, potential damage to the Engine Control Module (ECM). 

The high voltage surges can lead to thermal stress on the coil material and cause it to crack over time. These occurrences are unusual, but warrant heightened awareness for those operating within this vehicle segment.

4. Misfiring in Heavy Rain

During a heavy downpour, the Toyota Tundra experiences severe misfiring. Although replacing the spark plug initially appears to resolve the issue, it only provides a temporary fix as the problem resurfaces. 

Even after installing new coils and resetting the computer, the misfiring persists, with an OBD reader indicating an igniter malfunction on cylinder 3 with error code 1310. While it is unlikely that the plugs are causing the problem, swapping the number 3 plug with one from the opposite side for testing purposes is recommended. 

The error code pertains to the feedback signal to the computer, and in most cases, a faulty coil is to blame. To diagnose this issue effectively, using an oscilloscope is advised. Each coil connector features a 4-pin connector; when viewed from the wire side, pin 2 is located second from the right. 

For cylinder number 1, this will be a black wire with a red stripe; for cylinder number 2, it will be a black wire with a white stripe. To conduct testing, back probing of connector pin 2 from the wire side is necessary; inserting a pin next to the wire until it contacts the metal terminal at its end provides an external test point while keeping the connector connected.

How to Test an Ignition Coil on a Toyota Tundra

Testing the ignition coils in a Toyota Tundra can present challenges, but with the right tools and expertise, it is achievable. Here are various approaches that can assist in completing this task.

Visual Inspection 

When examining certain instances, it is possible to identify a malfunctioning ignition coil visually. Indicators like cracks, burn marks, and carbon tracking are signs of a defective coil. This is particularly relevant in the context of Toyota Tundra ignition coil issues and should be approached with expertise.

Swap the Ignition Coil

To determine if the misfire shifts, try switching the suspect ignition coil to a different cylinder. It’s advisable to have a scan tool or code reader on hand for this procedure. If you don’t have these tools, you can carry out a power balance test to assess each cylinder’s performance. 

Listen for changes in RPM as each cylinder is disabled; a minimal change indicates an issue. Note that factors other than a faulty coil, such as fuel delivery or engine mechanical problems, can cause RPM drops in specific cylinders. Swap it to another cylinder and repeat the power balance test to confirm if the coil is at fault. If the problem moves with the coil, it’s likely faulty.

Spark Test

To diagnose Toyota Tundra ignition coil issues, you can employ a spark tester to verify spark production. This device is connected in line with the ignition coil to assess its spark output. It’s crucial to choose a compatible spark tester for your specific ignition system, as not all testers are universally suitable. 

Opting for a high-quality, adjustable spark tester is advisable, as cheaper, non-adjustable alternatives may inaccurately indicate a weak spark. The process for utilizing a spark tester will differ based on the chosen tool and your vehicle’s ignition system.

Using Multimeter

To test a Toyota Tundra ignition coil using a multimeter, start by disconnecting the electrical connector from the ignition coil. Set your multimeter to measure resistance in the ohms (Ω) range. Connect the multimeter leads to the primary and secondary terminals of the ignition coil. The primary winding should have a resistance reading between 0.4 and 2 ohms, while the secondary winding should have a resistance reading between 6,000 and 30,000 ohms.

If either of these readings falls outside of the specified ranges, it indicates a faulty ignition coil that needs replacement. Additionally, inspect the ignition coil for any physical damage, such as cracks or corrosion, that could affect its performance. Testing the continuity of the ignition coil’s windings can also help identify any internal shorts or open circuits that could cause ignition issues.

Final Words

The Toyota Tundra ignition coil problems are a significant concern for owners of this popular truck model. The issues with the ignition coils have been well-documented and can lead to engine misfires, poor fuel economy, and even potential safety hazards. 

Toyota Tundra owners must be proactive in addressing these problems by regularly inspecting and maintaining their ignition coils. Additionally, seeking professional assistance at the first sign of trouble can help prevent more severe and costly damage in the long run.

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