OBD-II trouble code
P0261: Cylinder 1 Injector Circuit Low
SAE J2012 APR2002: cylinder 1 injector circuit low. On the 2009 Pontiac G3 that is an open or a short to ground, and the driver is the ground side. The printed pair is one injector.
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, RepairPal national average updated 3 September 2026; G3 wiring, the fuse, and the ECM are outside this pair)
- DIY difficulty
- Shop recommended
Browse every code in P0200–P0299, or start from the full code library.
What does P0261 mean?
SAE J2012 APR2002 names P0261 Cylinder 1 Injector Circuit Low. Circuit low is measured with the injector connected. P0262 is cylinder 1 circuit high. P0201 is cylinder 1 circuit/open, which section 3.1 uses when a high-or-low split is not the stored code. The cylinder number comes from the numbering diagram.
The 2009 Pontiac G3 procedure for P0261, P0262, P0264, P0265, P0267, P0268, P0270, or P0271 is one port-injection four-cylinder chart. Its fault table says a short to ground on the injector 1 control sets P0261 and P0300, an open or high resistance sets P0261 and P0300, and a short to voltage sets P0262 and P0300. The circuit description says ignition voltage is supplied to the injectors and the ECM grounds the control circuit with a driver. This is a low-side switch. The code runs with the engine running and ignition voltage between 11 and 16 volts, continuously, and the G3 calls these Type B codes. Setting one commands open-loop fuel.
The test order is the part that gets skipped. Ignition off, disconnect the injector. Ignition on, a test lamp from ignition terminal 2 to ground should light. If it does not, repair the ignition feed for a short to ground or an open, and replace the fuse if it opened. That is two feed faults, not a control-wire conclusion. Ignition off, connect special tool J 34730-405 between control terminal 1 and ignition terminal 2. Engine running, the lamp should flash. Keep hands off the belt and the fan. Always on: test the control wire for a short to ground; if that wire tests normal, replace the ECM. Always off: the chart says test for a short to voltage or an open; if the wire tests normal, replace the ECM. Do not replace the ECM on the always-on result before the short-to-ground test. If the circuits test normal, test or replace the injector.
Component resistance is 11–14 ohms between terminal 2 and terminal 1, ignition off, injector unplugged, and only when coolant is 10–32°C (50–90°F). Outside that window the G3 says the measurement is not accurate. Outside 11–14 ohms inside that window, replace the injector.
A different chart, the 3.6L LY7 procedure for P0261, P0264, P0267, P0270, P0273, or P0276, groups P0261 with P0267 and P0273 when the shared ignition feed for that bank is shorted to ground. Disconnecting the multi-way connector on that chart sets P0201–P0206 opens, which the procedure says to expect. Do not move the G3 terminal numbers onto that multi-way, and do not move the LY7 bank rule onto a G3.
RepairPal's fuel-injector replacement, updated 3 September 2026, removes the intake on the engines that job covers. Depressurize before a rail or an injector is opened. That page says to disconnect the battery when working with fuel, and it says the replacement is not a DIY repair. High-pressure fuel can penetrate skin on a direct-injection rail; the G3 chart is not that rail.
Common causes
- On the 2009 G3 table, injector 1 control shorted to ground, which sets P0261 and P0300
- On that same table, an open or high resistance in the injector 1 control, which also sets P0261 and P0300
- An ignition feed at terminal 2 that does not light a test lamp, repaired as a short to ground or an open, fuse included
- A control wire that holds the injector test lamp on, then a short-to-ground test, and only then the ECM
- An injector outside 11–14 ohms at 10–32°C, measured unplugged with the ignition off
- The LY7 case where P0261, P0267, and P0273 set together, which that chart treats as the bank feed
- A short to voltage, which the G3 table files as P0262, not as P0261
Symptoms
- P0261 stored
- P0300 stored with it on the G3 short-to-ground and open rows
- A test lamp at terminal 2 that stays dark, key on, injector unplugged
- J 34730-405 lit steady while the engine runs, which is the always-on branch
- Resistance outside 11–14 ohms inside the 10–32°C coolant window
Diagnostic steps
- 1.Identify cylinder 1 on the numbering diagram. The G3 terminals are terminal 2 ignition and terminal 1 control. The LY7 chart uses a multi-way and different code groups.
- 2.Ignition off, unplug the injector. Ignition on. Test lamp from terminal 2 to ground. No light: repair the ignition feed for a short to ground or an open, and replace the fuse if needed. Do not call that a control-wire short.
- 3.Ignition off. Connect J 34730-405 from terminal 1 to terminal 2. Engine running, the lamp should flash. Stay clear of the belt and the fan.
- 4.Lamp always on: test the control circuit for a short to ground with the right ends disconnected. Replace the ECM only if that wire tests normal. Lamp always off: the chart says short to voltage or open, then the ECM if the wire is normal. P0261's own descriptor on this car is the open or the short to ground, so write down which result you actually have.
- 5.If the circuits test normal, measure 11–14 ohms from terminal 2 to terminal 1, ignition off, unplugged, coolant 10–32°C. Outside 11–14 ohms, replace the injector. Outside 10–32°C, the G3 says not to trust the ohms.
- 6.On an LY7-style bank, P0261 plus P0267 plus P0273 points at the shared feed, not at three injectors. Expect P0201–P0206 if that multi-way is disconnected.
- 7.Depressurize before the injector comes out. Disconnect the battery before fuel work, which is RepairPal's instruction. The national injector average below is not a wiring repair and not an ECM.
- 8.Verify with the engine running and P0261 not returning, which is the G3 verification. The feed must still be in the 11–16 volt window for the monitor to run.
Repair cost
$768 – $953 (one fuel injector replacement, parts and labor, RepairPal national average updated 3 September 2026; G3 wiring, the fuse, and the ECM are outside this pair)
RepairPal's fuel injector replacement, updated 3 September 2026, is $768–$953 (labor $304–$446, parts $464–$507). The printed pair is that national average, for the injector the G3 replaces when the circuits test normal and the resistance is outside 11–14 ohms. Other vehicle lines on that estimator are outside the pair. A control-wire repair, a fuse, and an ECM are outside it. Diagnosis is $125–$183 labor and is separate. RepairPal says the job removes the intake on the engines it covers and is not a DIY repair.
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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.