P0016: what to check before buying parts
On this 4Runner, P0016 is the crankshaft/camshaft correlation code for Bank 1, Sensor A. The owner reports an intermittent check-engine light and worse fuel economy. The code tells us the relationship needs checking; it does not identify a failed sensor or a chain by itself.
- Save the complaint and scan results.
Record the codes, freeze-frame information where available, and when the light returns. Ask whether someone has been clearing it. That turns out to matter here.
- Check the oil and recent work.
Mike starts with level, condition, oil-change history and the oil/filter used. Look up the actual engine’s requirements and relevant service information before going deeper.
▶ Start with oil and service history Ep. 1 · 4:38 - See whether VVT responds—then respect the limit.
Commanding each bank changes how this engine runs. That is a quick response check. Mike explicitly says it does not prove the cam reaches the right target position.
▶ What the first VVT check cannot prove Ep. 1 · 9:38
Starting here as a DIY owner?
You can gather the symptoms, code history and oil-service information. The next tests need the right scope, current clamp, scan functions and wiring information. If those are outside your setup, use the shop brief to ask for evidence before authorizing a timing job.
This case is not clearance to keep driving with your own timing fault. New mechanical noise, an oil-pressure warning, severe rough running or stalling needs assessment before further running.
Confirm the engine first
The filmed engine is the 4.0L V6, 1GR-FE. Mike identifies a 2007 4Runner with a four-liter V6 in episode 1. At 1:35, the scan-tool screen shows 2007, 4RUNNER, 1GRFE and six cylinders.
▶ Hear the vehicle introduction Ep. 1 · 0:47▶ See the scan-tool vehicle selection Ep. 1 · 1:30Why does one video description say 4.7L?
Episode 2’s description conflicts with the vehicle shown and identified in the series. We use the direct video evidence here. Toyota’s 2007 specifications distinguish the 4.0L V6 from the 4.7L V8. This guide is not a 4.7L procedure, and it does not establish fitment or identical procedures for every vehicle using a 4.0L engine.
The evidence that earned the teardown
Each test answers a different question. Read down the table to see why Mike moves from a timing code to a mechanical inspection.
| Check | Observed result | Interpretation / next step |
|---|---|---|
| VVT response | In this 4RunnerBoth commanded banks change engine operation. | What that tells usA response exists. Target-position accuracy remains unproven; continue testing. |
| Relative compression | In this 4RunnerThe repeating starter-current pattern is lower for cylinders 1, 3 and 5. | What that tells usBank 1 deserves closer attention. This does not identify a failed chain or give absolute compression pressure. |
| Cam/crank scope comparison | In this 4RunnerBank 1 is displaced from the expected relationship; Bank 2 is closer. | What that tells usTiming correlation is wrong in the captured condition. Check direction, reference conditions and the mechanical cause. |
| Mechanical inspection | In this 4RunnerThe removed old chain hangs longer than the new chain in Mike’s comparison. Tensioner concerns are also inspected. | What that tells usThe teardown supports the wear diagnosis. No calibrated chain-length measurement is shown. |
| After repair | In this 4RunnerThe repeating bank-wide current difference is gone; cam/crank alignment improves at the reference point. | What that tells usThe original test findings have changed. Complete final checks and monitor/road verification before handover. |
Do not turn this into “every Toyota P0016 needs a chain.” A different signal, oil condition, actuator response or mechanical finding changes the next step.
Two scope tests, two different questions
Is there a repeating bank difference?
Mike uses a current clamp on the starter supply and an ignition reference from cylinder 4. With a consistent cranking sample, he assigns the repeating peaks to cylinders and compares banks.
His result: 1, 3 and 5 are repeatedly lower. That supports checking Bank 1 valve timing; it is not a measured compression-pressure result.
▶ Why starter current helps Ep. 2 · 4:26▶ Read the captured pattern Ep. 2 · 14:35Where are the cams relative to the crank?
He captures both cam signals and the crank signal together, using the Toyota reference shown in the video. The bank-to-bank relationship is wrong at the selected reference point.
His result: Bank 1 timing is displaced. The waveform supports opening the engine; it does not by itself show which guide, tensioner or chain is worn.
▶ Understand the reference pattern Ep. 3 · 2:13▶ Interpret the Bank 1 offset Ep. 3 · 19:24Technician setup: make the comparison meaningful
- Use the exact vehicle’s wiring and connector information. The video’s pin and wire choices are not universal probe instructions.
- For relative compression, use the prescribed no-start/cranking method and a stable cranking sample. Confirm the cylinder reference and firing order.
- For correlation, retain both cam channels and the crank reference. Match engine, operating condition, signal polarity and reference location to the comparison.
- Verify an absent trace before diagnosing it. Mike initially loses the crank signal and checks the test connection.
- Keep leads clear of belts and fans. Do not pierce shielded crank wiring to save access time.
Why the light comes and goes
The owner had been clearing the code. Mike explains that this case’s monitor needs an extended idle condition before it evaluates the timing relationship. A delay before the light returns therefore does not show that the chain moved back into time.
▶ Monitor conditions explain the returning light Ep. 4 · 1:43He then considers the direction of the timing error and compares it with another running vehicle. That is more useful than guessing from the word “intermittent.” His reasoning about VVT is specific to this engine and captured condition.
▶ Look at the direction of the offset Ep. 4 · 6:54▶ Compare with another running vehicle Ep. 4 · 35:09What in episode 4 is theory?
Mike explicitly labels his proposed analog-to-digital conversion threshold and the PCM’s exact decision point as speculation. We do not turn that model, its example voltage, or an estimated phase angle into a Toyota test specification. He revisits that uncertainty in episode 6. Use verified service information and a matched reference waveform for an actual pass/fail decision.
Before committing to the timing-chain job
The repair is in the vehicle, and episode 5 condenses a substantial teardown into key moments. Have the full Toyota service procedure for your application open before starting; this page helps you find the demonstrated checks.
Build the job plan first
- Access and safe support: lifting points, fluid handling, battery isolation and the prescribed disassembly order.
- Timing control: exact mechanical reference marks, safe cam/crank positioning, holding equipment and tensioner procedure.
- Parts and sealing: VIN-matched parts, required seals and replacement fasteners, sealant locations and cure requirements.
- Specifications: fastener torques, tightening sequences, oil/coolant requirements and refill/bleed procedure.
- Verification: manual timing checks before starting, then the original scope tests, leak checks and completed diagnostic monitors.
Mike describes replacing the chains, tensioners and guides; the finale also identifies new idler and crank sprockets. That describes this repair, not a universal shopping list. The series does not establish a part-number kit for your vehicle.
Timing-chain repair: jump to the important checks
Use these chapters alongside the full procedure. They are the useful checkpoints in Mike’s repair, including the mistake he catches and corrects.
- Inspect what the scope could not show.
With the front cover off, inspect the chain system, guides and tensioners. The old/new chain comparison supports the diagnosis, but Mike does not show a calibrated length result.
▶ Inspect behind the front cover Ep. 5 · 36:23▶ Old chain versus new chain Ep. 5 · 44:09 - Account for every loose piece.
A piece from a small-chain tensioner drops during disassembly. Mike retrieves it and checks the pieces together. Keep debris out of the engine and account for anything that breaks.
▶ Recover the tensioner piece Ep. 5 · 51:14 - Identify the bank-specific marks.
At the bench, he explains the single-dot reference for Bank 1 and double-dot reference for Bank 2 on the filmed components. Follow the exact service illustration; a dot or painted mark on a different part is not enough.
▶ Secondary-chain and bank references Ep. 5 · 55:41 - Check the crank reference—not just the colored links.
His initial installation looks promising, but the crank check reveals a one-tooth error. He stops, rechecks the references and corrects it. The earlier attempt is not the final installation to copy.
▶ Catch the one-tooth error Ep. 5 · 1:22:12▶ Return to the correction Ep. 5 · 1:25:48 - Verify the mechanical timing before starting.
After correction, he checks the marks, releases the tensioner and turns the engine by hand for the demonstrated recheck. Use the vehicle procedure for direction, position and checks; stop if it binds. Colored installation links need not return to the same places after two crank revolutions—use the specified mechanical references.
▶ Corrected alignment and tensioner check Ep. 5 · 1:26:50▶ Manual rotation and final marks Ep. 5 · 1:27:43
The video ends this repair stage before complete reassembly. It supplies no complete torque, sealant, refill or fastener-replacement specification. Those remain part of the job, even though they are off camera.
The engine runs. Now repeat the evidence.
Starting is not the final test. Mike reconnects the scope and repeats the checks that led him into the engine.
The bank-wide pattern is gone
The repeating three-low/three-high pattern no longer appears. Mike still notes a slightly lower cylinder 5 peak; he does not present a calibrated compression test or a perfect-all-cylinders claim.
▶ Compare compression before and after Ep. 6 · 4:07Compare the same reference
At the selected reference near the crank gap, the two cam traces now align closely. Compare the actual before/after captures, not an arbitrary pair of edges elsewhere in the cycle.
▶ See the repaired waveform Ep. 6 · 9:48Finish the checks off camera
He plans further driving to check for other issues. The series does not show the completed road test, all monitor results or a final no-leaks report.
▶ Hear what still needs checking Ep. 6 · 16:59Close the repair, not just the code
After the prescribed mechanical checks and reassembly, verify fluid levels, leaks and disturbed connections. Recheck codes and complete the applicable monitor conditions. Record the results and any remaining concern before returning the vehicle.
Bring this to the shop—or use it to explain the job
My vehicle / complaint: exact year and engine, symptoms, when the light returns, and whether codes were cleared.
Evidence to ask for: oil/service checks, which bank is affected, the cam/crank comparison and why the next step is mechanical inspection rather than a sensor replacement.
Repair scope: confirmed worn parts, matched parts/seals, complete reassembly requirements and approval before extra work.
Completion: corrected mechanical timing, comparable before/after tests, fluid/leak checks, code/monitor results and any unresolved concern.
This gives you useful questions without diagnosing your vehicle from someone else’s video.
Toyota P0016 questions
Does P0016 mean I need a camshaft sensor?
Not by itself. In this 4Runner, the signals helped expose a mechanical timing mismatch. A missing or abnormal signal would need its own electrical diagnosis. Prove what is wrong before choosing a part.
Does the Toyota 4.0L have just one timing chain?
The filmed engine has a main chain plus smaller chains between the intake and exhaust cams on each bank. Mike explains that layout with the cover off. Do not interpret his shorthand “single chain” as a complete parts count.
Why not use relative compression alone to condemn the chain?
It compares the cranking pattern across cylinders. The repeating Bank 1 difference justified further investigation, but it did not directly measure chain wear. The cam/crank comparison and physical inspection supplied different evidence.
Can I use this for a Tacoma, FJ Cruiser or 4.7L 4Runner?
This guide documents one 2007 4Runner 4.0L V6 case. It does not verify other model/year procedures or parts fitment. The 4.7L V8 is a different application; use its own service information.
Are the colored chain links supposed to line up after rotating the engine?
They are installation references. In the demonstration, Mike explains that they need not return after two crank revolutions. Follow the specified mechanical timing references and recheck procedure for the actual engine.
Did the final episode prove a completed long-term repair?
It shows improved relative compression and corrected cam/crank correlation at the selected reference. Mike plans more driving. A completed road/monitor report and long-term result are not shown.
Watch the six original episodes
Every timestamp above plays here. Use “Back to where you were” to return to the check you were reading.
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What this guide covers
This is a source-linked case companion for the filmed 2007 Toyota 4Runner 4.0L V6 (1GR-FE), not a complete factory repair procedure or an application list. Six caption files and the episode 1 scan-tool display support the guide. Episode 2’s 4.7L description conflicts with that direct evidence; it is not the application used here. Final cover sealing, complete reassembly, specified fastener torques and a completed road/monitor report are not supplied by the series. Use current, vehicle-specific service information for those steps.
Written by GoTech from the original videos. The linked source moments let you check the explanation against the demonstration.