P0135 on a 2017 Ram 1500
O2 Sensor Heater Circuit (Bank 1 Upstream)
P0135 on a 2017 Ram 1500 indicates o2 sensor heater circuit (bank 1 upstream). It usually stays drivable short-term but should be diagnosed promptly. The most common cause is failed o2 sensor heater element (open or shorted internally) (typically $150–$450). Confirm the root cause before replacing parts.
What does P0135 mean on a 2017 Ram 1500?
P0135 is set when the ECM detects that the heater element built into the Bank 1 upstream oxygen sensor is not drawing the expected current when commanded on. Zirconium O2 sensors only produce a usable signal above approximately 350 °C / 660 °F, so they include an internal heater that brings them to operating temperature quickly after cold start. P0135 means that heater is open, shorted, or being under-powered.
This guide covers P0135 across the 2015-2019 Ram 1500 generation — the symptoms, causes, and diagnostic steps below apply to every model year from 2015 through 2019.
Is it safe to drive a 2017 Ram 1500 with P0135?
In most cases a 2017 Ram 1500 stays drivable for short trips with P0135 active, but diagnose and repair it promptly. This is a moderate-severity code — ignoring it can lead to further damage or a failed emissions test.
What are the symptoms of P0135 on a 2017 Ram 1500?
- Check Engine Light is illuminated
- Extended open-loop fuel-trim period after cold start (worse fuel economy until warm)
- Slow O2 sensor switching that may take several minutes to begin after cold start
- Possible drivability symptoms if the engine remains in open loop too long
- Vehicle may fail emissions / smog test
What causes P0135 on a 2017 Ram 1500?
| Cause | Likelihood | Estimated repair (USD) |
|---|---|---|
| Failed O2 sensor heater element (open or shorted internally) | Most common | $150–$450 |
| Blown O2 heater fuse Always check the fuse before condemning the sensor. | Common | $5–$30 |
| Damaged sensor wiring (chafed against exhaust) | Common | $80–$350 |
| Corroded O2 sensor connector | Common | $30–$200 |
| Failed O2 heater relay (on vehicles with one) | Occasional | $30–$150 |
| Failed PCM driver for the heater circuit (rare) | Rare | $400–$1,500 |
How to diagnose this on a 2017 Ram 1500
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Check the O2 heater fuse first
Most vehicles route O2 heater power through a dedicated fuse, usually labeled "O2H" or "O2 SNSR" in the underhood fuse box. Replace any blown fuse with the exact amperage rating. If the fuse blows again immediately, the heater or its wiring is shorted.
Tools: Replacement fuse, Fuse puller
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Measure heater resistance at the sensor
Unplug the Bank 1 upstream O2 sensor. Measure resistance across the heater terminals (typically the two same-color wires — consult the wiring diagram). Expected resistance is approximately 3 to 15 Ω cold, depending on the sensor. Infinite resistance means an open heater; near zero means a shorted heater.
Tools: Multimeter, Wiring diagram
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Verify power and ground at the connector
With the key on and engine running, back-probe the heater power and ground wires. Battery voltage should be present on power and a clean ground on the other side. Missing voltage points to the fuse, the wiring, or the PCM driver.
Tools: Multimeter, Back-probe pins
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Measure heater current draw
A working heater draws approximately 0.8 to 2 A depending on sensor design. Use a low-current clamp around the heater wire, or a multimeter in series. Current of 0 A with voltage present means the heater is open. Current well above 2 A means the heater is partially shorted and will fail soon.
Tools: Multimeter with current function, Low-current clamp (preferred)
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Inspect the sensor and its wiring for physical damage
O2 sensor harnesses run close to hot exhaust components and are a common chafing victim. Inspect the wiring from the connector to the sensor body. Heat-damaged insulation, melted plastic, or visible copper requires harness repair or replacement, not just a new sensor.
Tools: Flashlight, Wire repair supplies
NHTSA complaints & recalls for the 2017 Ram 1500
Owner-reported safety complaints and official recalls filed with the U.S. National Highway Traffic Safety Administration for the 2017 Ram 1500. Use these to gauge how common a problem is on your specific vehicle before you start chasing Ram 1500 diagnostics.
- ENGINE 154
- POWER TRAIN 97
- STEERING 215
- ELECTRICAL SYSTEM 102
- SERVICE BRAKES 91
13 active recalls
- ENGINE AND ENGINE COOLING:ENGINE:DIESEL Aug 2020
Chrysler (FCA US LLC) is recalling certain 2014-2018 Ram 1500 and 2014-2016 Jeep Grand Cherokee vehicles equipped with 3.0L diesel engines. The crankshaft position sensor tone wheel may delaminate causing the engine to lose its ability to synchronize the fuel injector pulses and…
NHTSA campaign 20V475000 - LATCHES/LOCKS/LINKAGES:TAILGATE:LATCH May 2019
Chrysler (FCA US LLC) is recalling certain 2015-2017 Ram 1500, 2500 and 3500 pickup trucks equipped with an 8 foot bed and a power locking tailgate. Chrysler is also recalling all 2013-2014 and 2018 Ram 1500, 2500 and 3500 pickup trucks built before April 1, 2018 with a 6 or 8 f…
NHTSA campaign 19V347000 - STRUCTURE:BODY:TAILGATE Jul 2018
Chrysler (FCA US LLC) is recalling certain 2015-2017 RAM 1500, 2500, and 3500 pickup trucks equipped with a power locking tailgate and either a 5 foot, 7 inch or 6 foot, 4 inch bed. The tailgate actuator limiter tab may fracture and cause the tailgate to unlatch and open while d…
NHTSA campaign 18V486000 - ELECTRICAL SYSTEM:WIRING May 2018
Chrysler (FCA US LLC) is recalling certain 2014-2018 Dodge Journey, Charger and Durango, RAM 2500, 3500, 3500 Cab Chassis (more than 10,000lb), 4500 Cab Chassis and 5500 Cab Chassis, Jeep Cherokee and Grand Cherokee and Chrysler 300, 2014-2019 RAM 1500, 2015-2018 Dodge Challenger…
NHTSA campaign 18V332000
How do I fix P0135 on a 2017 Ram 1500?
- Replace the Bank 1 upstream O2 sensor with an OEM part
- Replace the O2 heater fuse
- Repair damaged O2 sensor wiring
- Replace the O2 heater relay
- Clean or repair the O2 sensor connector
About the 2015-2019 Ram 1500
The 2015-2019 Ram 1500 was commonly sold with the following powertrains: 5.7L HEMI V8, 3.6L V6, 3.0L EcoDiesel V6. Common trims include Tradesman, Big Horn, Laramie, Rebel, Limited.
Why heater failure matters
Zirconium O2 sensors produce no usable signal until they reach about 350 °C. Without the heater, the sensor waits for exhaust heat to bring it up to temperature — which can take 5+ minutes of driving. During that period the ECM runs in “open loop” mode, using a calibrated fueling map rather than O2 feedback. This is fine briefly but causes poor cold-running emissions and 10–20 % worse fuel economy while the heater is dead.
P0135 with the sensor only weeks old
Aftermarket O2 sensors fail at much higher rates than OEM. If P0135 appeared shortly after an O2 sensor replacement with a non-OEM part, the new sensor itself is the most likely problem. Warranty-exchange for an OEM-equivalent before chasing the wiring.
Heater current and the “weak heater”
A heater that draws low current but is not fully open is a “weak” heater. It will warm the sensor partially, allowing the sensor to work but slowly. The ECM eventually sets P0135 even though the heater is not fully dead. A current measurement is the only reliable way to catch this failure mode — a simple resistance check often misses it.
P0135 on a 2017 Ram 1500: frequently asked questions
What does diagnostic trouble code P0135 mean on a 2017 Ram 1500?
P0135 is set when the ECM detects that the heater element built into the Bank 1 upstream oxygen sensor is not drawing the expected current when commanded on. Zirconium O2 sensors only produce a usable signal above approximately 350 °C / 660 °F, so they include an internal heater that brings them to operating temperature quickly after cold start. P0135 means that heater is open, shorted, or being under-powered.
What are the symptoms of P0135 on a 2017 Ram 1500?
Check Engine Light is illuminated. Extended open-loop fuel-trim period after cold start (worse fuel economy until warm). Slow O2 sensor switching that may take several minutes to begin after cold start. Possible drivability symptoms if the engine remains in open loop too long. Vehicle may fail emissions / smog test
What causes P0135 on a 2017 Ram 1500?
Failed O2 sensor heater element (open or shorted internally) (most-common). Blown O2 heater fuse (common). Damaged sensor wiring (chafed against exhaust) (common). Corroded O2 sensor connector (common). Failed O2 heater relay (on vehicles with one) (occasional). Failed PCM driver for the heater circuit (rare) (rare)
Is it safe to drive a 2017 Ram 1500 with P0135?
In most cases a 2017 Ram 1500 stays drivable for short trips with P0135 active, but it should be diagnosed and repaired promptly — this is a moderate-severity code. Ignoring it can lead to further damage or a failed emissions test.