Toyota Runx: M20A-FKS Timing Chain Cold-Start Rattle

On 2019–2021 production M20A-FKS 2.0-litre engines, the timing chain tensioner spring rate was insufficient to maintain adequate chain tension during the brief oil-starvation window at cold start. The resulting slack allows the chain to slap the guide, producing a pronounced metallic rattle for 1–5 seconds that diminishes once oil pressure builds. Toyota addressed the root cause via TSB T-SB-0067-19, which specifies replacement of the chain tensioner assembly with a revised part and a recalibrated ECU fuel-cut map to reduce instantaneous torque during cold-crank.

• Metallic rattling or chattering noise on cold start lasting 1–5 seconds
• Noise originates from front-left of engine and disappears once oil pressure builds
• Check Engine light in severe or neglected cases (P0016/P0017 cam-crank correlation codes)
• Rattling may worsen in cold ambient temperatures below 10 degrees Celsius
• Oil consumption slightly elevated on affected units

1. 1

   Start engine from dead-cold and listen immediately for metallic chain rattle from the front-left of the engine.

2. 2

   Check service records for TSB T-SB-0067-19 application and tensioner replacement.

3. 3

   Inspect oil level and condition — low or degraded oil worsens onset.

Parts involved: Timing chain.

$800 to $2,800 at New Zealand independent workshop rates. That is for this job on its own, not for the car.

An estimate, in NZD, for the repair as normally carried out. What a specific car costs depends on which part has failed and what it damaged on the way — treat this as the floor for a negotiation, not a quote.

• “Has the timing chain tensioner been replaced under TSB T-SB-0067-19, and can you show the dealer service record?”
• “Does the engine make any rattling or ticking noise when started cold first thing in the morning?”
• “Has the vehicle ever shown a Check Engine light related to camshaft or crankshaft position codes?”

The failure described above is documented in published sources — owner forums, technical service bulletins, recall notices and workshop write-ups — held in our fault database. The inspection instructions and the cost estimate are KickTyres’ own interpretation of them, and it is a starting point for an inspection rather than a manufacturer statement.