PCM WranglerFix: P0516 & Fixed Battery Temp Reading on 2005 TJ

[heinrichmeza]

Hi everyone,

I recently sent an email to WranglerFix about this and I’m waiting for their response, but I wanted to post here as well in case anyone has seen the same issue. Maybe it can also help others who run into something similar.

Vehicle details:

• 2005 Jeep Wrangler TJ SE
• 4.0L, 42RLE

Background:

After installing the PCM a few months ago, my transmission issue was completely resolved (thanks WranglerFix!). However, ever since then I’ve been seeing DTC P0516 – Battery Temperature Sensor Circuit Low right at key-ON.

What I tested:

• Monitored live data for Battery Temp and BATT TEMP SIGNAL.
• Tried the circuit open (no sensor), with resistors (4.7 kΩ, 10 kΩ, 22 kΩ), and with the actual sensor (~8.7 kΩ at ~34 °C).
• Verified wiring continuity from the connector to the PCM.
• In all cases, the scanner always reports ~34 °C (≈1.92 V). The value never changes regardless of resistance applied.

Notes:

• It looks like the calibration is substituting a fixed default value (~34 °C) instead of reading the BTS.
• The P0516 code does not appear on the instrument cluster, only when scanned.
• I don’t mind the code itself, but I want to confirm if this is normal behavior and if it’s safe for long-term use, especially in a warm climate (La Paz, Mexico).

Question:

Do WranglerFix PCMs intentionally fix the BTS reading to ~34 °C?
Has anyone else with a WranglerFix PCM seen this P0516 code at key-ON?

Any feedback would be really helpful — both for me and for anyone else who might face the same situation.

Thanks,
Enrique Meza

 

[macleanflood]

Tangentially relevant but I messed with the battery temperature sensor on my 97 with a stock PCM trying to raise the charge voltage for my Optima Yellow Top AGM battery (hecho en Mexico, creo.) Never got the charge voltage high enough and I'm resigned that at some point I'm going to need to purchase HP Tuners to mess with it.

I'm sure @Wranglerfix Mark will sort things out.

Bueno suerte.

-Mac

 

[heinrichmeza]

Tangentially relevant but I messed with the battery temperature sensor on my 97 with a stock PCM trying to raise the charge voltage for my Optima Yellow Top AGM battery (hecho en Mexico, creo.) Never got the charge voltage high enough and I'm resigned that at some point I'm going to need to purchase HP Tuners to mess with it.

I'm sure @Wranglerfix Mark will sort things out.

Bueno suerte.

-Mac

Thanks a lot for your reply and for sharing your experience . It’s good to know how the stock PCM behaved on your ’97 when you tried to play with the BTS input.

I already heard back from Mark — he told me he’ll review this with one of his technicians. As soon as I get a more detailed response from @Wranglerfix , I’ll come back here and share it so it can hopefully help others too.

Appreciate the input and encouragement!

Enrique Meza