P0332 Code on a GMC: Knock Sensor Circuit Low, Bank 2 (GMC Guide)

P0332 on a GMC is "Knock Sensor (KS) Circuit Low, Bank 2." It does not mean the engine is knocking. On a 2007-and-later Sierra, Yukon or Savana V8 it is an electrical test: the engine control module (ECM) biases each knock sensor circuit with a small voltage, and P0332 sets when the bank 2 circuit is pulled too low — typically a wire shorted toward ground. GM's bulletin for 2014–2019 Sierra and Yukon trucks traces P0332 to the engine harness rubbing on the vacuum pump pulley, and the fix is wiring. On a 1999–2002 Sierra or Yukon the story is a corroded sensor under the intake. And here is the surprise: on a 2004 Envoy, which has no bank 2 at all, GM's tables still list P0332 — for the inline six's second knock sensor.

What Does P0332 Mean on a GMC?

A knock sensor is a piezoelectric microphone bolted to the engine. When combustion detonates, the block rings at a characteristic frequency; the sensor converts the vibration to a voltage, and the ECM retards spark to protect the engine. A GMC V8 has two knock sensors, one per bank.

P0332 is the sensor 2 / bank 2 circuit reading low. Bank 2 on a Sierra, Yukon or Savana V8 is the passenger side (cylinders 2-4-6-8); GM's 2002–2003 truck tables call it the "rear knock sensor." On the transverse 3.6L in the Acadia and Terrain, bank 2 is the front bank. Its sister codes are P0327 and P0328 (sensor 1 low and high) and P0330 and P0333 (sensor 2 general and high).

GM's 2002 table for the 4.3L and truck V8s notes that P0332 is "for use on 2 sensor applications." If your engine has only one knock sensor, it should not set P0332 — re-check the code and the scan tool.

When a knock sensor circuit fails, the ECM cannot hear detonation on that bank and generally runs more conservative spark timing. That is where the power and fuel economy loss comes from.

How GM's Test Works by Generation

All of these are Type B codes in the tables we read — normally two failed trips before the check engine light comes on.

2014–2019 Sierra and Yukon: The Vacuum Pump Pulley

GM's PIT5307F covers the 2014–2018 Sierra 1500, the 2019 Sierra Limited and the 2015–2019 Yukon with the 5.3L L83 or 6.2L L86. The complaint list is long — check engine light, ABS light, "Service Suspension System," misfire, hesitation, low engine power, erratic shifting, no crank, A/C inoperative, a low oil level message, and blown starter or A/C clutch fuses — and the DTC list includes P0332 along with P0324–P0333, P0335, P0340 and chassis codes.

GM's cause is one point: the engine harness rubbing on the engine vacuum pump pulley. The repair: fix the damaged circuits and re-secure the harness away from the pulley. No knock sensor is listed.

That fits the Gen V test exactly. A chafed knock sensor wire touching a grounded part drags the bias voltage down — the "circuit low" condition. If your Sierra or Yukon has P0332 along with unrelated warnings, check this harness before anything else.

GM's 20-NA-207 (2014–2018 Sierra, 2015–2020 Yukon) covers the opposite code, P0333 — bank 2 high — when shifting out of Park, caused by voltage from the transmission park/neutral signal circuit bleeding into the knock sensor circuits. GM directs inspection of the ECM's X2 connector for debris and terminal problems. Different code, same lesson: on these trucks, knock sensor codes are usually wiring and connectors.

1999–2002 Sierra and Yukon: Water Under the Intake

NHTSA's index lists GM bulletin 02-06-04-023 (and revision 023A) for the 1999–2002 Sierra and 2000–2002 Yukon: mild to severe engine ping (spark knock), usually worse during acceleration, and/or a check engine light with P0332. The documents are not in NHTSA's archive. Reproduced copies we read for our Chevrolet research describe the cause and repair:

• Water enters the sensor cavity and corrodes the rear knock sensor — frequent engine washing makes it worse.
• Remove the intake manifold and replace the rear knock sensor (GM part 10456603), torqued to 20 N·m (15 lb-ft).
• Run a bead of RTV around the sensor on the valley cover but leave the rear open so water can drain, and remove the rear foam intake seal.

We mark those details corroborated rather than verified because we have not read the GM original. They match GM's own 2002–2003 tables, which call the bank 2 sensor the "rear knock sensor" and set P0332 when that sensor goes quiet — exactly what a corroded sensor does. And they mean that on these trucks the sensors sit under the intake, so the repair is labor-heavy. Some technicians report repeat failures even after new sensors, so check sensor output after the repair rather than assuming it is fixed.

Envoy and Canyon: "Bank 2" on an Inline Engine

The Envoy's 4.2L LL8 is an inline six — one bank — but it uses two knock sensors. GM's 2004 table lists them as "ESC Sensor 1" (P0327) and "ESC Sensor 2" (P0332). On a 2004 Envoy, then, P0332 points at the second sensor and its circuit, not at a "passenger side."

GM's 2004 table for the Canyon's 2.8L LK5 and 3.5L L52 also lists P0332, labeled "Knock Sensor Circuit Low Voltage – Bank 2," with the same voltage-range test as bank 1. These are inline engines too. Check service information for how many knock sensors your Canyon has before you go looking for a second one.

By 2006, GM's combined table for the 2.8L and 4.2L lists P0325 and P0327 but no P0332. On a 2006-or-later Envoy or Canyon inline engine, a P0332 on a generic scanner deserves a second look with a GM-capable tool.

We found no GM bulletin that names P0332 on a Canyon, Envoy, Terrain or Acadia.

Symptoms of P0332 on a GMC

• Check engine light on
• Reduced power or sluggish acceleration as the ECM runs conservative timing
• Poorer fuel economy
• Audible spark knock on a 1999–2002 Sierra or Yukon with a corroded rear sensor
• ABS, suspension, A/C or no-crank complaints at the same time on 2014–2019 Sierra and Yukon trucks
• P0327 alongside if wiring shared by both sensors is damaged

Causes and How to Confirm Each

How Is P0332 Diagnosed on a GMC?

1. Note the engine and generation. It decides whether you are chasing a bias-voltage fault, a quiet sensor or an inline engine's second sensor.
2. Record every code in every module. A crowd of unrelated codes on a 2014–2019 Sierra or Yukon points straight at PIT5307F.
3. Inspect the harness at the vacuum pump pulley on Gen V trucks.
4. Check connectors at the sensor and at the ECM.
5. Test the circuits for shorts to ground and continuity per the wiring diagram.
6. On a 1999–2002 truck, plan for intake removal if the sensor is the problem, and follow GM's drain-path RTV method.
7. Replace the sensor only after the wiring tests good, and torque it to specification.
8. Clear the code and drive through the conditions the monitor needs — on Gen III, a warm engine between 1,500 and 3,000 rpm.

Parts and Cost

If you replace a sensor, order by VIN and torque it to specification. An overtightened or loose knock sensor does not hear the block correctly.

GM Documents That Name P0332 on GMC Models

Have a dealer check your VIN against current bulletins rather than relying on any article, including this one. The check is free.

What Other P0332 Pages Get Wrong

• "P0332 means your engine is knocking." It is a circuit or signal fault. The engine may be perfectly healthy.
• "Replace the knock sensor." On 2014–2019 Sierra and Yukon trucks, GM's own bulletin fixes P0332 with wiring repair at the vacuum pump pulley.
• "Bank 2 is always the passenger side." On a GMC V8, yes. On a 2004 Envoy inline six, P0332 is the second knock sensor.
• Confusing P0332 with P0333. Low and high point at different faults — low is usually a short toward ground; GM's P0333 bulletin points at voltage bleeding in from another circuit.
• Skipping torque. A loose sensor is a quiet sensor, and a quiet sensor sets the older trucks' test. For the Chevrolet side of this code, see our P0332 guide for Chevrolet.

Frequently Asked Questions

Is it safe to drive my GMC with P0332?

Usually in the short term — the ECM generally runs conservative timing when it cannot hear knock. Expect less power and economy. Avoid heavy towing and low-octane fuel until it is fixed.

Which side is bank 2 on a Sierra or Yukon?

The passenger side, cylinders 2-4-6-8. GM's older truck tables call it the rear knock sensor.

Do I have to remove the intake to fix P0332?

On a 1999–2002 Sierra or Yukon with a failed sensor, GM's bulletin repair does. On a 2014–2019 truck, check the harness at the vacuum pump pulley first — GM's PIT5307F fixes it without intake removal.

Why does my Yukon have P0332 with ABS and A/C warnings?

That mix is GM's PIT5307F pattern on 2015–2019 Yukons and 2014–2019 Sierras: the engine harness rubbing on the vacuum pump pulley damages several circuits at once.

How can an Envoy set a bank 2 code?

GM's 2004 table for the Envoy's 4.2L inline six uses P0332 for "ESC Sensor 2," the second knock sensor. It does not mean the engine has a second bank.

What's the difference between P0332 and P0327?

Same fault, other sensor. P0327 is sensor 1 (bank 1, driver side on a GMC V8); P0332 is sensor 2 (bank 2). Both at once suggests damage to wiring shared by both sensors.