2000 Volvo S70 AWD Won’t Start: Crankshaft Sensor, ETM, and What to Check First

ByKenji Alvarez

If Your 2000 Volvo S70 AWD Won’t Start, Check These First

A no-start on the S70 is frustrating partly because the usual suspects aren’t always what you’d expect. Fuel injectors come up constantly in forum threads, and they’re worth testing. But the crankshaft position sensor and the electronic throttle module cause far more starting failures on these cars. Here’s how to work through it.

Start With a Scan — But Use the Right Tool

Scanning for codes is the right first move, but a standard OBD-II reader won’t surface everything. Volvo-specific faults, especially ETM-related codes, often require a VIDA/DICE interface or a scan tool with genuine Volvo coverage. A generic reader might return nothing, leading you to assume no stored fault when there actually is one.

If you pull throttle-related DTCs like P0121, P0221, or P2135, the ETM is almost certainly the issue. If the screen comes back clean, don’t stop there. Check live data and move on to physical testing.

The Crankshaft Position Sensor

The CPS is responsible for a large number of S70 no-start complaints. The pattern is distinctive: starts normally when cold, then refuses to fire after the engine has been off for 20 to 30 minutes. The tachometer may jump erratically during cranking, or sit completely still.

When the CPS signal drops out, the ECU has no timing reference for spark and injection. The engine cranks. It just never catches. On the V70/S70 platform this sensor is prone to heat-related failure. It can test fine at ambient temperature and still fail when hot.

Testing is straightforward with a DVOM: you should see around 50 millivolts AC at the sensor while cranking. No signal, or an intermittent one, points squarely at the CPS. Replacement is not expensive and the job is accessible.

The ETM: A Known Volvo Weak Point

Late S70 models used an electronic throttle module made by Magneti Marelli. It replaced the mechanical cable throttle with a fly-by-wire system, and it developed a well-documented failure mode: the internal throttle position sensor contacts wear down, causing erratic or absent throttle signals.

When the ETM starts failing, you might see the engine start and immediately enter limp mode — very rough running, a hard rev limit around 2,000 RPM, check engine light on. In some cases it won’t start at all. Codes P0121, P0221, or P2135 are the giveaway.

Several specialists rebuild ETMs for less than the cost of a new unit. Throttle body cleaning is worth doing first since carbon buildup can mimic ETM failure, but if cleaning doesn’t resolve it, the sensor contacts are worn out.

Fuel Injectors and Fuel Delivery

A single bad injector more typically causes rough idle, misfires, or a fuel smell than a complete no-start. A total failure to start from fuel delivery usually points upstream to the pump or a clogged filter.

Quick check: cycle the ignition key a few times without cranking (key to ‘on,’ wait a couple of seconds, key off) to prime the system, then try starting. If it fires immediately on first crank after priming when it normally cranks and cranks, the fuel pump check valve is leaking and pressure is bleeding down while the car sits. That’s a pump problem, not an injector problem.

For injector-specific testing you need a fuel pressure gauge and a noid light. Good pressure at spec with no injector pulse signal points to wiring or ECU. Low pressure with correct pulse signal points to the injector or pump.

Other Sensors Worth Ruling Out

The mass airflow sensor is a common fault on this platform. A failing MAF usually causes rough running and weak power before a no-start, but a completely dead one can prevent starting. Unplug it and see if behavior changes — the ECU will run on a default map without the signal.

The coolant temperature sensor affects fuel mixture during cold starts. A sensor stuck reading a very high temperature tricks the ECU into running lean on a cold engine. The symptom is the reverse of the CPS pattern: won’t start cold, fires up after sitting a while.

Where to Start

  • Scan with a Volvo-capable tool first, not just a generic OBD-II reader
  • Throttle codes (P0121, P0221, P2135) — clean the throttle body, then evaluate the ETM
  • No codes and won’t restart when hot — test the CPS with a DVOM while cranking
  • Check fuel pressure with a gauge before chasing injectors
  • Test the MAF by unplugging it; if behavior improves, replace it
  • Injector testing comes last

The CPS and ETM together account for a disproportionate share of no-start and rough-running complaints on this platform. Injectors are the last thing to blame, not the first.

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