P0153 on RAM: How to Diagnose & Fix
O2 Sensor Circuit Slow Response (Bank 2, Sensor 1)
1 RAM model · 1 documented issue · $500-$1,800 repair
On RAM vehicles, P0153 (o2 sensor circuit slow response (bank 2, sensor 1)) is most often reported on the 2009-2018 RAM 1500 as Broken Exhaust Manifold Bolts on the 5.7L HEMI Leak Air Into the Bank 2 Sensor ($500-$1,800 repair). Confirm the leak before buying parts. Listen at the passenger-side manifold flange on a cold start for a rhythmic tick or hiss that fades as the engine warms, then inspect each manifold bolt from underneath - a snapped bolt often leaves a visible gap, soot fanning out from the port, or a shiny witness mark where the flange has been moving. Each section below gives the symptoms, how to confirm the cause, the fix, parts and sources for that model.
Common causes of P0153 (all vehicles)
- Aged or contaminated upstream O2 sensor (bank 2)
- Exhaust leak near the sensor
- Vacuum leak affecting air-fuel ratio
- Wiring or connector corrosion at the sensor
- Sensor contamination (oil, coolant, silicone)
- Low fuel pressure or fuel delivery issues
- Faulty sensor heater circuit
P0153 on RAM by model: symptoms, diagnosis and fix
The 5.7L HEMI's exhaust manifold bolts, particularly the rearmost ones on each head, are a well-documented failure item. Repeated heat cycling stretches and eventually snaps them, and once a bolt lets go the manifold lifts off the head just enough to open a gap at that port. On the bank 2 (passenger-side) manifold the resulting leak is upstream of the bank 2 sensor 1 oxygen sensor, so the sensor is measuring a stream that has been diluted with outside air pulled in during the negative-pressure part of each exhaust pulse. The transitions the PCM is timing get smeared, the measured switch time runs past the calibrated limit, and P0153 is stored. The same defect is behind the notorious cold-start 'HEMI tick' - the leak whistles or ticks while the metal is cold and contracted, and quiets once thermal expansion closes the gap, which is why many owners hear the noise for a couple of minutes each morning and then dismiss it. A cracked manifold produces an identical picture. Because the leak also skews the fuel trims and can push a false lean condition downstream, P0153 on these trucks is often accompanied by P0171/P0174 lean codes or catalyst codes, and shops that skip the leak test end up selling a sensor - or worse, a catalytic converter - that does not fix the complaint. Chrysler has also issued a PCM software update (TSB 18-050-21) for trucks setting P0153 together with P0133, P0171, P0174 and P0300, so a reflash should be checked for before parts are bought. A related but separate version of this failure shows up on HEMI trucks fitted with aftermarket long-tube headers, where the relocated O2 bung sits farther from the port, sees cooler and slower-moving gas, and sets the same slow-response code on an otherwise healthy sensor.
Common Symptoms
- Check engine light with P0153, sometimes with P0133, P0171/P0174 lean codes or catalyst codes
- Cold-start ticking or hissing from the passenger-side exhaust manifold that fades as the engine warms
- Exhaust smell noticeable at idle
- Reduced fuel economy
- Slight hesitation or uneven idle
- P0153 returns after a new bank 2 sensor 1 is installed
How to Fix
Confirm the leak before buying parts. Listen at the passenger-side manifold flange on a cold start for a rhythmic tick or hiss that fades as the engine warms, then inspect each manifold bolt from underneath - a snapped bolt often leaves a visible gap, soot fanning out from the port, or a shiny witness mark where the flange has been moving. A smoke test of the exhaust or a propane test at the flange while watching short-term fuel trims will confirm it. The accepted repair is to remove the manifold, extract the broken bolt stubs from the cylinder head, and reassemble with new gaskets and an upgraded bolt or stud kit; many shops fit revised hardware or a stud-and-nut conversion so the joint can be serviced without drilling next time. If a bolt broke flush or below the deck surface it must be drilled and extracted with the head in place, which is the difference between a moderate bill and a large one. Replace the manifold outright if it is cracked rather than merely unbolted. Check for the applicable PCM software update (TSB 18-050-21 covers P0153 set with P0133, P0171, P0174 and P0300) at the same time, since a reflash is a known remedy for the oversensitive O2 monitor on this platform. Once the exhaust is sealed, verify the bank 2 sensor 1 signal on a scan tool at operating temperature; if it is still sluggish, fit a genuine Mopar or NTK sensor - owners report generic replacements re-setting slow-response codes even when the exhaust is sound. On trucks with aftermarket headers, the fix is usually a bung relocated closer to the collector, an O2 extender removed, header wrap to keep gas temperature up, or a calibration change to the slow-response monitor rather than another sensor.
Looking for P0153 on a different make?
View P0153 across all makes →Frequently asked questions
What does P0153 mean on a RAM?
P0153 stands for "O2 Sensor Circuit Slow Response (Bank 2, Sensor 1)." This code indicates the upstream oxygen sensor on bank 2 is switching too slowly between rich and lean signals. The computer depends on a fast-responding sensor to continuously adjust the fuel mixture for that bank. When the sensor's response time is below the required threshold, this code is stored. It generally causes poorer fuel economy and increased emissions, and is the bank 2 counterpart to P0133. On RAM it is documented across 1 model: 1500.
How do I diagnose P0153 on a RAM 1500?
Confirm the leak before buying parts. Listen at the passenger-side manifold flange on a cold start for a rhythmic tick or hiss that fades as the engine warms, then inspect each manifold bolt from underneath - a snapped bolt often leaves a visible gap, soot fanning out from the port, or a shiny witness mark where the flange has been moving. A smoke test of the exhaust or a propane test at the flange while watching short-term fuel trims will confirm it. Published repair guidance and available estimates are in the 1500 section on this page.
What causes P0153 on RAM vehicles?
Documented causes on RAM: Broken Exhaust Manifold Bolts on the 5.7L HEMI Leak Air Into the Bank 2 Sensor. Generic causes of P0153: Aged or contaminated upstream O2 sensor (bank 2), Exhaust leak near the sensor, Vacuum leak affecting air-fuel ratio, Wiring or connector corrosion at the sensor.
How much does it cost to fix P0153 on a RAM?
Published repair estimates on RAM range from $500 to $1,800 depending on the model and root cause. If an issue mentions a recall or campaign, check your VIN with the manufacturer or NHTSA and confirm eligibility and coverage with a dealer.
Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.