OBD-II trouble code
P0270: Cylinder 4 Injector Circuit Low
SAE J2012 APR2002: cylinder 4 injector circuit low. The 2007 BMW M5 S85 memory line is a short to ground and a 3500 rpm limit. The printed pair is one injector after the plug is checked.
Quick facts
- System
- Powertrain
- Category
- Fuel Injectors
- Severity
- Medium severity
- Drivable
- Usually safe to drive short-term
- Repair cost range
- $768 – $953 (one fuel injector replacement, parts and labor, after the 2007 M5 harness step or the G3/G8 circuit tests; the short to ground and the module are outside this pair)
- DIY difficulty
- Shop recommended
Browse every code in P0200–P0299, or start from the full code library.
What does P0270 mean?
SAE J2012 APR2002 names P0270 Cylinder 4 Injector Circuit Low. P0271 is cylinder 4 circuit high. A VAG-group list prints 16654 P0270 as injector 4-N33, short-circuit to ground.
The 2007 BMW M5 (E60) S85 page is fault 276A - P0270, electrical diagnosis of cylinder 4's fuel injector. Memory entry: driver info includes a short circuit to ground. Terminal 15 must be on and battery voltage must be above K_ED_PlusMin. Service action: check the plug and wiring harness on the injection valve, then check the valve and replace as indicated. The effect line is rough idle, engine speed limited to 3500 rpm, power reduction, and the MIL after the engine runs twice. A 2009 M5 page uses the same hex 276A for P0271 and a short to B+, with a 5000 rpm limit. Do not read the 2009 high-code page as this 2007 low-code page.
The 2009 G3 1.6L chart includes an open in P0270 as well as a short to ground. A short to voltage is P0271. On the 7.5–16 V Type A procedure, AllOEMManuals G3 L4-1.6L and gm.saturn.team 7725/145178, terminal 1 is ignition and terminal 2 is control. Document 8100/175665 swaps those terminals and prints 11–16 V, Type B, so these pins are not every 2009 G3 connector. The feed lamp comes before J 34730-405, and 11–14 ohms applies only at 10–32°C. When coolant is outside 10–32°C, the G3 coil-test page does not use 11–14 ohms. It compares injectors: the highest minus the lowest should be equal to or less than 3 ohms. If the spread is greater than 3 ohms, the page averages the set and replaces the injector with the greatest difference from that average. That comparison is the G3's, and it is not the M5 page, which prints no ohms.
The 2008 G8 files P0270 only as a short to ground for greater than 4 seconds or a cumulative of 30 seconds. The open is P0204. The 2007 LY7 chart treats P0264, P0270, and P0276 together as the other bank's ignition feed shorted to ground. One code alone on that chart is the single control wire. A lamp to B+ on the injector side of the multi-way that lights means the short is between the multi-way and the injectors. A lamp that stays dark means the short is between the multi-way and the fuse. Do not swap those two results.
Common causes
- On the 2007 M5, a short circuit to ground in cylinder 4's injector driver info, fault 276A
- A short to ground in that injection valve's plug or harness
- On the 7.5–16 V Type A G3 procedure, injector 4's control circuit open or shorted to ground
- On the G8, a short to ground held for greater than 4 seconds or a cumulative of 30 seconds
- On the 2007 LY7 chart, the shared bank ignition feed shorted to ground
Symptoms
- P0270 stored
- On the 2007 M5 page, speed limited to 3500 rpm and a power reduction
- A G3 feed lamp at terminal 1 that stays dark
- A G8 control-pin lamp to B+ that lights
- P0264 and P0276 stored with it on the LY7 bank row
Diagnostic steps
- 1.On a 2007 M5, check the plug and harness on cylinder 4's injection valve before the valve. The 3500 rpm limit is the effect line. Do not use the 2009 page that files 276A as P0271 and a short to B+.
- 2.On the 7.5–16 V Type A procedure, prove ignition terminal 1 lights a lamp, key on, injector unplugged. A dark lamp is the ignition feed, not this control fault. Then J 34730-405 from control terminal 2 to ignition terminal 1 with the engine running. Always on is the short-to-ground path. Always off still has to be split into a short to voltage, which is P0271, and an open, which this setting line does include. The G8 stores an open as P0204. The 2009 M5 page that reuses hex 276A is P0271.
- 3.Inside 10–32°C, the 7.5–16 V Type A procedure measures 11–14 ohms from ignition terminal 1 to control terminal 2. Outside that window, use the equal-to-or-less-than-3-ohm spread, then the average, and replace the injector farthest from the average.
- 4.On a G8, the low code is the short to ground only. Expect P0201–P0206 when the multi-way is opened. Control pin to B+ must stay dark.
- 5.On the LY7 trio, a lamp to B+ that lights localizes the feed short to the injector side of the multi-way. A dark lamp localizes it to the fuse side. Then remove the upper intake only for the injector-side repair.
- 6.Depressurize before the injector is removed. The printed pair is one injector. The harness and the module are outside it.
Repair cost
$768 – $953 (one fuel injector replacement, parts and labor, after the 2007 M5 harness step or the G3/G8 circuit tests; the short to ground and the module are outside this pair)
RepairPal's national injector replacement, 3 September 2026, is $768–$953 (labor $304–$446, parts $464–$507). The printed pair is that average once the chart says to replace the valve or the injector. It is not the 3500 rpm symptom and not a harness repair. Diagnosis at $125–$183 is separate. The 2026 Tucson line, $456–$604, and the 2026 F-150 line, $1,130–$1,415, are other lines on the estimator and stay outside the pair.
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DIY vs shop
Leave this one to a qualified shop. The barrier here is high-pressure fuel components, where residual pressure remains after shutdown and escaping fuel can penetrate skin. DIY attempts often produce a more expensive problem than the original code.